Effect of Solvents Fractions of Cucurbita maxima Cuticular Lipids on Metabolic Biomarkers of Cardiovascular Disease

This study was aimed at studying the effect of solvents (n-hexane, chloroform and methanol) fractions of Cucurbita maxima (pumpkin) cuticular lipids on metabolic biomarkers of cardiovascular disease using L-NAME induced hypertensive rats. A total of thirty-six (120-150 g) albino rats were randomly selected and placed into twelve groups of three rats each were used for this study. Each rat was weighed and tagged and thereafter weighed weekly for five weeks of the experiment. Rats were induced with hypertension using 40mg/Kg body weight/24hours. Other rats were placed on normal feeds and water while biomarkers were assayed and recorded on weekly basis. Group I served as normal control, Group II were hypertensive control, Group III were induced with hypertension and administered with standard drug while Groups IV-XII were induced with hypertension and administered with varying doses of n-hexane, chloroform and methanol fractions. A slight alteration on metabolic biomarkers between the normal control group and hypertensive control group was recorded, which was reversed by the administration of methanol fraction. Thus, cuticular lipids from Cucurbita maxima might have some anti-hypertensive potentials.

Canagliflozin reduces the contractile response of isolated heart of normal adult rats / Canagliflozin reduce la respuesta contráctil del corazón aislado de ratas adultas normales

SUMMARY: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) represent a unique class of glucose-declining renal-targeted drugs. The SGLT2i Canagliflozin (CANA) is an anti-hyperglycemic drug that reduces various cardiovascular and renal outcomes in patients with type 2 diabetes mellitus. This study aimed to explore the potential effects of CANA on the isolated healthy adult rat hearts to show if CANA has positive inotropic or cardiac depressant effects via analyzing the amplitude and frequency of cardiac contractions. In isolated normal adult rat hearts, the effects of CANA on cardiac contractility were examined. In a dose-response curve, CANA led to a significant cardiac depressant effect in a dose-dependent manner. This cardiac depressant effect of CANA (10-6 M) was not prevented by atropine. However, this cardiac depressant effect was partially antagonized by both Isoproterenol (10-5 M) and Calcium chloride (10-6 M), suggesting beta-adrenoceptor and calcium channel blocking actions. In addition, the cardiac depressant effect of CANA (10-6 M) was mitigated in part by Nitric oxide synthase inhibitor, L-NAME, suggesting that its action probably depends to some extent on the accumulation of nitric oxide, which decreases the rise of intracellular Calcium. Data from this study demonstrate that CANA has a significant cardiac relaxant effect in isolated hearts of healthy adult rats by different possible mechanisms. This inhibitory effect on cardiac contractility may help improve the diastolic ventricular filling providing a therapeutic potential to help the other cardioprotective mechanisms of CANA in the prevention and treatment of heart failure.

RESUMEN: Los inhibidores del cotransportador de sodio- glucosa 2 (SGLT2i) representan una clase única de fármacos dirigidos a los riñones que disminuyen la glucosa. El SGLT2i Canagliflozin (CANA) es un fármaco antihiperglucémico que reduce varios resultados cardiovasculares y renales en pacientes con diabetes mellitus tipo 2. Este estudio tuvo como objetivo explorar los efectos potenciales de CANA en corazones aislados de ratas adultas sanas para indicar si CANA tiene efectos inotrópicos o depresores cardíacos positivos mediante el análisis de la amplitud y la frecuencia de las contracciones cardíacas. En corazones aislados de ratas adultas normales, se examinaron los efectos de CANA sobre la contractilidad cardíaca. En una curva de dosis-respuesta, CANA condujo a un efecto depresor cardíaco significativo de manera dependiente de la dosis. Este efecto depresor cardíaco de CANA (10-6 M) no fue impedido por la atropina. Sin embargo, este efecto depresor cardíaco fue parcialmente antagonizado tanto por el isoproterenol (10-5 M) como por el cloruro de calcio (10-6 M), lo que sugiere acciones bloqueadoras de los receptores beta adrenérgicos y de los canales de calcio. Además, el efecto depresor cardíaco de CANA (10-6 M) fue mitigado en parte por el inhibidor de la sintasa de óxido nítrico, L-NAME, lo que sugiere que su acción probablemente depende en cierta medida de la acumulación de óxido nítrico, lo que disminuye el aumento de calcio intracelular. Los datos de este estudio demuestran que CANA tiene un efecto relajante cardíaco significativo en corazones aislados de ratas adultas sanas por diferentes mecanismos posibles. Este efecto inhibitorio sobre la contractilidad cardíaca puede ayudar a mejorar el llenado ventricular diastólico proporcionando un potencial terapéutico para ayudar a los otros mecanismos cardioprotectores de CANA en la prevención y tratamiento de la insuficiencia cardíaca.

Passiflora quadrangularis L. prevents experimental hypertension and vascular remodelling in rats exposed to nitric oxide deficit / Passiflora quadrangularis L. previene la hipertensión experimental y el remodelado vascular en ratas expuestas a déficit de óxido nítrico

Background: Passiflora quadrangularis L. is among the species used in Colombian folk medicine for hypertension, but until now it has not been studied in experimental models. Objectives: To assess the capacity of P. quadrangularis L. EtOH extract to prevent the hypertension and vascular remodelling induced by nitric oxide (NO) deficit in Wistar rats. Methods: The nitric oxide (NO) synthase inhibitor L-NAME (10 mg/kg, i.p (intraperitoneal), every 48h) was administered for seven weeks to the following groups of rats: P. quadrangularis L.75, 150 and 300 mg/kg/d, p.o. (oral route); enalapril as reference agent, 10 mg/kg/d, p.o. and vehicle as control (mixture of propylene glycol 10%, glycerine 10% and polysorbate 2%). Arterial blood pressure (BP) and heart rate (HR) were measured twice a week. After sacrifice, the aortic rings were isolated, contraction was triggered with phenylephrine (PE 10-6 M) and then the relaxant response achieved with cumulative concentrations of acetylcholine (ACh, 10-10 ­ 10-5 M) or sodium nitroprusside (SNP, 10-10 ­ 10-5 M) was assessed. Histopathologic measures of thickness/lumen ratio from both the left ventricle and aorta walls, as well as phytochemical screening, were also performed. Results: As for enalapril, all doses of P. quadrangularis L. prevented the hypertension induced by L-NAME (122±1.2 versus 155±1.3 mmHg at seventh week). P. quadrangularis L. significantly increased the relaxant effect induced by ACh in isolated aorta and decreased the thickness/lumen ratio of aorta wall specimens. Conclusions: P. quadrangularis L. prevents experimental hypertension induced in rats with nitric oxide deficits improving the endothelium vasodilatation response and protecting against vascular remodelling.

Antecedentes: Passiflora quadrangularis L. es una de las especies utilizadas en medicina tradicional en Colombia para la hipertensión pero hasta el momento no se ha evaluado en modelos experimentales. Objetivos: Evaluar la capacidad del extracto etanólico de P. quadrangularis L. para prevenir la hipertensión y el remodelado vascular inducidos por déficit de óxido nítrico (NO) en ratas Wistar. Métodos: El inhibidor de la óxido nítrico (NO) sintasa L-NAME (10 mg/kg, i.p, cada 48 h) se administró durante siete semanas a los siguientes grupos de tratamiento: P. quadrangularis L. 75, 150 y 300 mg/kg/d, p.o; Enalapril como agente de referencia, 10 mg/kg/d, p.o., y vehículo como control (mezcla de propilenglicol 10%, glicerina 10% y polisorbato 2%). Se midió la presión arterial (BP) y la frecuencia cardiaca (HR) dos veces por semana. Después del sacrificio, se aislaron los anillos aórticos, se desencadenó la contracción con fenilefrina (PE 10-6 M) y la respuesta relajante con concentraciones acumulativas de acetilcolina (ACh, 10-10 ­ 10-5 M) o nitroprusiato de sodio (SNP, 10-10 ­ 10-5 M). También se realizaron estudios histopatológicos de la relación entre el espesor y el lumen tanto en el ventrículo izquierdo como en las paredes de la aorta, así como un cribado fitoquímico. Resultados: Enalapril y todas las dosis de P. quadrangularis L. evitaron la hipertensión inducida por L-NAME (122 ± 1,2 frente a 155 ± 1,3 mm Hg a la séptima semana). P. quadrangularis L. aumentó significativamente el efecto relajante inducido por ACh en la aorta aislada y disminuyó la relación entre el espesor y la luz de los especímenes en la pared de la aorta. Conclusiones: P. quadrangularis L. previene la hipertensión experimental inducida por déficit de óxido nítrico en ratas, mejorando la respuesta del endotelio y protegiendo frente al remodelado vascular.

Expression of Class I and Class II a/b Histone Deacetylase is Dysregulated in Hypertensive Animal Models

BACKGROUND AND OBJECTIVES: Dysregulation of histone deacetylase expression and enzymatic activity is associated with a number of diseases. It has been reported that protein levels of histone deacetylase (HDAC)1 and HDAC5 increase during human pulmonary hypertension, and that the enzymatic activity of HDAC6 is induced in a chronic hypertensive animal model. This study investigated the protein expression profiles of class I and II a/b HDACs in three systemic hypertension models. SUBJECTS AND METHODS: We used three different hypertensive animal models: (i) Wistar-Kyoto rats (n=8) and spontaneously hypertensive rats (SHR; n=8), (ii) mice infused with saline or angiotensin II to induce hypertension, via osmotic mini-pump for 2 weeks, and (iii) mice that were allowed to drink L-N(G)-nitro-L-arginine methyl ester (L-NAME) to induce hypertension. RESULTS: SHR showed high systolic, diastolic, and mean blood pressures. Similar increases in systolic blood pressure were observed in angiotensin II or L-NAME-induced hypertensive mice. In SHR, class IIa HDAC (HDAC4, 5, and 7) and class IIb HDAC (HDAC6 and 10) protein expression were significantly increased. In addition, a HDAC3 protein expression was induced in SHR. However, in L-NAME mice, class IIa HDAC protein levels (HDAC4, 5, 7, and 9) were significantly reduced. HDAC8 protein levels were significantly reduced both in angiotensin II mice and in SHR. CONCLUSION: These results indicate that dysregulation of class I and class II HDAC protein is closely associated with chronic hypertension.

Histological evaluation of the rat dental pulp after indirect capping with sildenafil or L-NAME incorporated into a bioadhesive thermoresponsive system / Avaliação histológica da polpa dental do rato após capeamento pulpar indireto usando sildenafil ou L-NAME incorporados a um sistema bioadesivo termorresponsivo

We evaluated the histological dental pulp state in vivo after indirect pulp capping using sildenafil or LG-nitro-L-arginine (L-NAME), incorporated into a new bioadhesive thermoresponsive system (BTS). Male Wistar rats were subjected to an upper and lower first molar class I cavity preparation followed by indirect pulp capping with sildenafil or L-NAME. Calcium hydroxide (CaOH2) was used as a control. The teeth and surrounding bone were properly dissected and processed for Nissl's staining. Pulp state was evaluated considering the morphological aspects of the inflammatory response, type of inflammatory infiltrate, organization of the odontoblast layer, blood vessel condition, and presence of abscesses or necrosis. The results were expressed as average of observations. The most intense inflammatory response was observed 3 days after the cavity preparation. No identified changes were detected in the dental pulp response of the molars treated with L-NAME compared with those treated with CaOH2. A dual effect was observed in the teeth treated with sildenafil. While low sildenafil concentration (0.015% w w-1) promoted effects comparable to CaOH2, at a higher concentration (0.15% w w-1), sildenafil caused a severe inflammatory response and pulp necrosis. This pioneering suggest that NO pathway activity may be a determinant in the process of dental pulp healing.

Avaliou-se o estado histológico da polpa dental in vivo após capeamento pulpar indireto usando sildenafil ou LG-nitro-L-arginine (L-NAME), incorporados num novo sistema bioadesivo termorresponsivo (BTS). Ratos Wistar machos foram sujeitos ao preparo cavitário, classe I nos primeiros molares superiores e inferiores, seguido de capeamento pulpar indireto com sildenafil ou L-NAME incorporados em BTS. Hidróxido de cálcio (CaOH2) foi usado como controle positivo. Os dentes e tecidos adjacentes foram adequadamente dissecados e processados para a coloração de Nissl. O estado da polpa foi avaliado quanto aos aspectos morfológicos e tipo do infiltrado inflamatório, organização da camada de odontoblastos, condições dos vasos sanguíneos e presença de abcesso ou necrose. A reposta inflamatória mais intensa foi observada três dias após o preparo cavitário. Nenhuma alteração foi detectada na polpa dental dos molares tratados com L-NAME comparados com aqueles tratados com CaOH2. Um efeito dual foi observado nos dentes tratados com sildenafil. Enquanto baixas concentrações de sildenafil (0.015% v v-1) promoveram efeitos comparáveis com o CaOH2, altas concentrações (0.15% v v-1) causaram uma severa resposta inflamatória e necrose pulpar. Este estudo pioneiro sugere que a atividade da via do NO pode ser determinante no processo de cicatrização.

Guanidinoacetate alters antioxidant defenses and butyrylcholinesterase activity in the blood of rats

Deficiency of guanidinoacetate methyltransferase, the first described creatine biosynthesis defect, leads to depletion of creatine and phosphocreatine, and accumulation of guanidinoacetate (GAA) in brain and body fluids. The present study aimed to investigate the influence of GAA on the activities of antioxidant enzymes, as well as on thiobarbituric acid-reactive substances (TBARS) and butyrylcholinesterase (BuChE) activity in the blood of rats. We also evaluated the effect of trolox (6-hydr oxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), GSH (glutathione) and L-NAME (NG-nitro-L-arginine methyl ester) on the alterations elicited by GAA. Methods: The rats were randomly divided into 8 groups: (1) control; (2) GAA (10, 30, 50, 100 mM/kg); (3) trolox (1 mM/kg) + control; (4) trolox (1 mM/kg) + GAA (100 mM/kg); (5) GSH (1 mM/kg) + control; (6) GSH (1 mM/kg) + GAA (100 mM/kg); (7) L-NAME (1 mM/kg) + control; (8) L-NAME + GAA (100 mM/kg). After the addition of compounds, erythrocytes and plasma were pre-incubated at 37°C for 1h and tested immediately. Results: GAA enhanced the activities of catalase (CAT) and glutathione peroxidase (GSH-Px) in the erythrocytes and BuChE activity. In addition, GAA enhanced TBARS levels in the plasma. Trolox, GSH and L-NAME addition prevented the majority of alterations in oxidative stress parameters and the increase of BuChE activity that were caused by GAA. Data suggest that GAA alters antioxidant defenses and induces lipid peroxidation in the blood, as well altering BuChE activity. However, in the presence of trolox, GSH and L-NAME some of these alterations in oxidative stress and BuChE activity were prevented. Conclusions: Our findings lend support to a potential therapeutic strategy for this condition, which may include the use of appropriate antioxidants for ameliorating the damage caused by GAA...

Efecto hipotensor del extracto de ajo (Allium sativum) macerado por 18 semanas en un modelo experimental in vivo / Hypotensive effect of extract of macerated garlic (Allium sativum) for 18 weeks in an in vivo experimental model

Objetivos. Determinar si el extracto de ajo (Allium sativum) macerado por 18 semanas tiene igual o mejor efecto hipotensor que el captopril en ratas. Materiales y métodos. Se realizó un estudio experimental in vivo con ratas machos Holtzman, clasificados en cinco grupos: 100, 500 y 1000 mg/kg de extracto de ajo, Captopril de 100 mg/kg y un grupo vehículo. El L-NAME (N-G-nitro L-arginina-metil-éster) administrado vía intraperitoneal 50 mg/kg desde el inicio del experimento, elevó la presión arterial desde el tercer día. El análisis estadístico consistió en las pruebas T de Student para medias pareadas, ANOVA y comparación múltiple de Scheffe. Resultados. El ajo macerado extraído por un proceso hidroalcohólico durante 18 semanas provocó una disminución de la presión arterial en animales de experimentación. El análisis de los tratamientos sobre la presión arterial media (PAM), obtuvieron diferencias significativas desde el tercer día. La comparación sobre la PAM final versus PAM basal (medias no diferentes) y el efecto hipotensor (%) fueron: ajo-100 (p=0,008), 59,8%; ajo-500 (p=0,021), 80,6%; ajo-1000 (p=0,034), 88,5%, Captopril (p=0,437), 99,9% y vehículo (p=0,001), 0%. Conclusiones. El ajo macerado a un periodo de 18 semanas resultó eficaz para producir un efecto hipotensor en ratas, inducidas a hipertensión arterial por L-NAME...

Objectives. Determine whether macerated extract of garlic (Allium sativum) for 18 weeks is equal to or better than Captopril in its hypotensive effect in rats. Materials and methods. We performed an experimental in vivo study with Holtzman male rats divided into five groups using 100, 500 and 1,000 mg kg of garlic extract, Captopril 100 mg/kg and a vehicle group. 50 mg/kg L-NAME (NG-nitro-L-arginine methyl ester) was administered intraperitoneally which elevated blood pressure after the third day. Statistical analysis consisted of StudentÆs t-test for paired means, ANOVA and Scheffe multiple comparison. Results. The macerated garlic extracted by a hydroalcoholic process administered for 18 weeks resulted in a decrease in blood pressure in experimental animals. In the analysis of treatments on mean arterial pressure (MAP), significant differences were obtained after the third day. The comparison of the MAP final versus MAP basal (no difference in averages) and the hypotensive effect (%) were: garlic-100 (p=0.008), 59.8%; ajo-500 (p=0.021), 80.6%; garlic-1000 (p=0.034), 88.5%; captopril (p=0.437), 99.9%; and vehicle-only (p=0.001), 0%. Conclusions. The macerated garlic given for an 18-week period effectively produced a hypotensive effect in rats with hypertension induced by L-NAME...

Estudo da superposição de mecanismos fisiopatológicos como modelo de hipertensão arterial com repercussões cardíacas graves / Study of overlap of pathophysiologicalmechanisms as a model of hypertensionwith severe cardiac effects

Fundamento: Acredita-se que o rato espontaneamente hipertenso (SHR) mimetize a hipertensão arterial (HA) essencial em humanos. Lesões em órgãos-alvo nesses animais não são devidas unicamente ao aumento da pressão arterial. Outros mecanismos fisiopatológicos superajuntados talvez representem melhor o complexo dano cardiovascular observado também em humanos. Objetivo: avaliar, comparativamente, as alterações cardíacas em ratos SHR nos quais mecanismos outros de HA (renovascular, hipervolemia, disfunção endotelial) sejam superpostos. Materiais e Métodos: cinco grupos foram estudados: Controle (C,n=11); SHR (n=11); SHR + L-NAME (SHR + L-NAME, n=11); SHR com estenose cirúrgica de artéria renal (SHR + 2R-1C, n=11); SHR+ deoxicorticosterona e cloreto de sódio 0,9% (SHR+DOCA-SALT, n = 11). Foram avaliados pressão arterial caudal (PAC), hipertrofia do ventrículo esquerdo (VE) e alterações histológicas miocárdicas. Resultados: Após oito semanas, os grupos SHR + L-NAME, SHR + 2R-1C e SHR + DOCA-SALT mantiveram PAC semelhante e mais elevada que os animais SHR (159,9 ± 8,3; 162,7± 16,7 e 166,3 ± 6,7 versus 138±7,8, respectivamente), bem como a espessura relativa da parede do VE (SHR + L-NAME = 0,64 ± 0,06; SHR+DOCA-SALT=0,63 ± 0,07 versus SHR=0,57±0,03) (p < 0,05). Amassa relativa do VE dogrupo SHR+ L-NAME (4,2±1,15) foi maior que nos demais grupos (SHR=2,8±0,5; SHR + 2R-1C=3,2±0,5; SHR + DOCA-SALT = 3,1 ± 0,2) (p <0,05). O desarranjo de fibras, fibrose intersticial, espessura médio-intimal aumentada foram mais frequentes nos ratos SHR + L-NAME. Conclusão: O modelo SHR + L-NAME mostrou repercussões cardíacas mais evidentes que os demais modelos de HA, fato não explicado apenas pelos níveis de PA elevados. Tal modelo pode ser utilizado em estudos futuros como representativo de maior comprometimento cardíaco na HA grave ou em estados avançados da doença.

Background: Spontaneously hypertensive rats (SHR) are believed to mimic arterial hypertension (HA) essential in humans. The injuries on targeted organs on these animals are not due only to increased blood pressure. Other pathophysiological mechanisms may represent better the superimposed complex cardiovascular damage observed on humans as well. Objective: comparatively evaluate the cardiac abnormalities in SHR in which other mechanisms of hypertension (renovascular, fluid overload and endothelial dysfunction) are superimposed. Materials and Methods: 5 groups were studied: Control (C, n=11); SHR (n = 11); SHR + L-NAME (SHR + L-NAME, n= 11), SHR with surgical stenosis of renal artery (SHR+ 2K-1C, n = 11), SHR + deoxycorticosterone and sodium chloride 0.9% (SHR + DOCA-SALT, n = 11). The blood pressure flow (PAC), left ventricular hypertrophy (VE) (echocardiography) and myocardial histological changes were evaluated. Results:After 8 weeks, the SHR + L-NAME, SHR + 2K-1C and SHR + DOCA-SALT groups maintained similar and higher PAC than SHR (159.9 ± 8.3, 162.7 ± 16.7 and 166.3 ± 6.7 versus 138± 7.8, respectively) as well as the relative thickness of the VE wall (SHR + L-NAME = 0.64 ± 0.06, SHR + DOCA-SALT= 0, 63 ± 0.07 versus SHR = 0.57 ±0.03;) (p < 0.05). The relative LV mass (MRVE, mg/g) of the group SHR + L-NAME (4.2 ± 1.15) was higher than in other groups (SHR = 2.8 ± 0.5, SHR + 2K-1C = 3.2±0.5, SHR + DOCA-SALT = 3.1 ± 0.2) (p < 0.05). Fiber disarray, interstitial fibrosis and the increased of intima-media thickness were more frequent in SHR + L-NAME. Conclusion: SHR + L-NAME showed cardiac effects more evident than the other models of hypertension, which was not explained only by high levels of PA. This model can be used in future studies as representative of greater cardiac involvement in hypertension or severe stages of the disease.

Metallothionein-1 and nitric oxide expression are inversely correlated in a murine model of Chagas disease

Chagas disease, caused by Trypanosoma cruzi, represents an endemic among Latin America countries. The participation of free radicals, especially nitric oxide (NO), has been demonstrated in the pathophysiology of seropositive individuals with T. cruzi. In Chagas disease, increased NO contributes to the development of cardiomyopathy and megacolon. Metallothioneins (MTs) are efficient free radicals scavengers of NO in vitro and in vivo. Here, we developed a murine model of the chronic phase of Chagas disease using endemic T. cruzi RyCH1 in BALB/c mice, which were divided into four groups: infected non-treated (Inf), infected N-monomethyl-L-arginine treated (Inf L-NAME), non-infected L-NAME treated and non-infected vehicle-treated. We determined blood parasitaemia and NO levels, the extent of parasite nests in tissues and liver MT-I expression levels. It was observed that NO levels were increasing in Inf mice in a time-dependent manner. Inf L-NAME mice had fewer T. cruzi nests in cardiac and skeletal muscle with decreased blood NO levels at day 135 post infection. This affect was negatively correlated with an increase of MT-I expression (r = -0.8462, p < 0.0001). In conclusion, we determined that in Chagas disease, an unknown inhibitory mechanism reduces MT-I expression, allowing augmented NO levels.

The levels of NO decrease induced apoptosis in human placental trophoblast cells through oxidative stress / 中国药理学通报

Aim To investigate the possible mecha-nisms of the levels of NO decrease induced apoptosis in human placental trophoblast cells. Methods Human placental trophoblast cells ( HTR-8 ) were cultured in 5 ml DMEM-F12 culture medium with 37℃ 5% CO2 . Then, the old culture medium was discarded and re-placed with 10,100,500,1 000 μmol·L-1 L-NAME, and the group without L-NAME was set as the control group, cultured for 48h. The effects of L-NAME on the survival of cells were detected by methylthiazolyldiphe-nyl tetrazolium bromide ( MTT); the content of NO in cells was tested by nitrate reductive enzymatic;trans-mission electron microscopy, flow cytometry analysis and Annexin-V FITC dyeing were used to test the effects of L-NAME on apoptosis in HTR-8 cells;restore Fe3+ colorimetric assay was applied for detection of to-tal antioxidant capacity ( T-AOC ) , xanthine oxidase for detection of superoxide dismutase ( SOD) activity, and thiobarbituric acid colorimetry for determination of content of MDA. Results Compared with the control group, the survival rate of HTR-8 cells and the levels of NO in 100,500,1 000 μmol·L-1 L-NAME group were significantly reduced(P<0.05,P<0.01). Flow analysis and Annexin-V FITC staining showed that L-NAME could induce cell apoptosis in a dose-dependent manner. The number of cell apoptosis was negatively correlated with the content of NO ( r = -0.5210 ) in HTR-8 cells. Transmission electron microscopy results showed that compared with the control group, the ex-perimental group's cell nucleus shape was irregular, nuclear pyknosis in irregular shape, the chromatin ag-glutination or side the collection, mitochondrial swell-ing or enrichment, crest fracture or dissolved, even vanished, forming the vacuole, especially in 100 μmol ·L-1 L-NAME group, the apoptotic bodies obviously appeared. At the same time, T-AOC, SOD levels in HTR-8 cells decreased ( P <0.05 ) , and the MDA content increased ( P<0.05 ) . The number of cell ap-optosis was negatively correlated with the level of T-AOC ( r= -0.3212 ) , SOD ( r= -0.2779 ) in HTR-8 cells , while positively correlated with the content of MDA(r=0.2807). Conclusion Oxidative stress may play an important role in the levels of NO decrease in-duced apoptosis in human placental trophoblast cells.

Efeito do agonista PPAR LYSO-7 sobre a instalação e cicatrização de úlceras gástricas induzidas em camundongos / Effect of PPAR agonist LYSO-7 on installation and healing of gastric ulcers induced in mice

A úlcera gástrica é uma doença crônica, de alta prevalência, e a eficácia dos tratamentos farmacológicos disponíveis é limitada pela alta incidência de efeitos adversos. Neste trabalho é mostrado o mecanismo de ação terapêutica e os efeitos toxicológicos da molécula indol-tiazolidínica LYSO-7 em diferentes modelos experimentais de úlcera gástrica. Camundongos Swiss machos foram tratados com veículo, LYSO-7 (5, 25 ou 50 mg/kg, v.o.) ou bezafibrato (25 ou 50 mg/kg, v.o.) 1 hora antes da administração oral de Et/HCl (60%/0,03 M) ou indometacina (100 mg/kg). Em outro conjunto de ensaios, animais foram pré-tratados com GW9962, um antagonista PPARγ (2 mg/kg, i.p.); anticorpo anti-granulócito (50 µL, i.p.), ou L-NAME (70 mg/kg, i.p) 1 hora antes dos tratamentos com veículo ou LYSO-7. Uma hora após administração da solução de Et/HCl, os neutrófilos foram quantificados no sangue e medula óssea, a rede microcirculatória gástrica foi estudada em in situ, utilizando a técnica de microscopia intravital; o tecido gástrico foi utilizado para quantificar a percentagem de área lesada, atividade da MPO, a expressão gênica e proteica de PPARγ, expressão proteica de iNOS e eNOS, e a atividade das enzimas catalase, SOD, GPx, GR e GST. Uma hora após a administração de indometacina, o tecido gástrico foi removido para avaliar a eficácia do tratamento e a secreção de mediadores inflamatórios. Ensaio de úlcera crônica, induzida por ácido acético, foi realizado em camundongos Balb/c WT ou ANXA1-/-, aplicando-se 20µL de ácido acético na camada subserosa do estômago e 24 horas após a indução, os animais foram tratados, uma vez ao dia, durante sete dias com LYSO-7 (50 mg/kg), bezafibrato (50 mg/kg) ou veículo. Foram realizados ensaios com macrófagos recrutados para o peritônio pela ação do tioglicolato de sódio (3%, i.p.) e com neutrófilos recrutados pela ação do glicogênio de ostra (1%, i.p.). Ensaios de toxicologia aguda, crônica e mutagenicidade também foram realizados. Os resultados obtidos mostram que o tratamento com LYSO-7 reduz a área lesada, o influxo de neutrófilos e a estase da rede microcirculatória provocada pela administração de Et/HCl. Os efeitos protetores foram revertidos em animais pré-tratados com GW9962, indicando a participação do PPARγ no efeito. O influxo de neutrófilos é determinante para a lesão, uma vez que a depleção destas células reduziu a ulceração gástrica, e indica que o bloqueio da mobilização de neutrófilos da medula óssea para o sangue e destes para o tecido lesado pela LYSO-7 pode ser um mecanismo de ação gastroprotetora desta molécula. A reversão da estase vascular na microcirculação, mas não o influxo de neutrófilos, é mediado pelo NO, pois o pré-tratamento com L-NAME aboliu os efeitos da LYSO-7 no restabelecimento do fluxo sanguíneo da microcirculação. Este efeito pode ser dependente da maior e menor expressão proteica de eNOS e iNOS, respectivamente. A LYSO-7 foi capaz de alterar favoravelmente a atividade das enzimas antioxidantes no tecido gástrico. Ainda, a LYSO-7 diminuiu a área lesada e reduziu a concentração de TNFα e aumentou a de IL-10 no tecido gástrico lesado pela indometacina. Na resolução do processo inflamatório, o tratamento com LYSO-7 diminuiu a percentagem de área lesada, aumentou a apoptose de neutrófilos e a eferocitose de neutrófilos por macrófagos peritoneais, inibiu a secreção de TNFα e aumentou a secreção de IL-10, TFG-1ß e VEGF para o sobrenadante de macrófagos em fagocitose. A resolução de lesão gástrica, bem como a indução da fagocitose pela LYSO-7 foi reduzida em animais ANXA1-/-. As investigações destes últimos dados mostraram a relação da ANXA1 e PPARγ, já que a expressão do receptor é reduzida em macrófagos obtidos de animais depletados de ANXA1. Os estudos toxicológicos mostraram que a LYSO-7 apresenta baixa toxicidade aguda e crônica in vivo, além de não ocasionar mutagenicidade em eritrócitos da medula óssea. Os dados obtidos mostram que a molécula LYSO-7 atua como agonista PPARγ na modulação da úlcera gástrica e modula a migração de neutrófilos e o fluxo sanguíneo na microcirculação. A transativação e transrepressão de eNOS e iNOS, respectivamente, o bloqueio da migração de neutrófilos para a lesão e a inibição da atividade de enzimas oxidativa, ativação de enzimas antioxidantes no epitélio gástrico e a inibição da secreção de mediadores inflamatórios parecem ser os mecanismos de ação da LYSO-7 na citoproteção gástrica. Adicionalmente, a LYSO-7 atua na resolução do processo inflamatório promovendo downregulation na secreção de mediadores inflamatórios, aumento na apoptose de neutrófilos e eferocitose de neutrófilos apoptóticos

Gastric ulcer is a chronic disease that presents high prevalence, and effectiveness of pharmacological treatments available is limited by several adverse effects. In this study is shown the mechanism of action and toxicological effects of the molecule indole-thiazolidine LYSO-7 in different models of gastric ulcer. Male Swiss mice were treated with vehicle LYSO-7 (5, 25, or 50 mg/kg, p.o.) or bezafibrate (25 or 50 mg/kg, p.o.) 1 hour before the oral administration of Et/HCl (60%/0.03 M) or indomethacin (100 mg/kg). In another set of assays, animals were pre-treated with GW9962, a PPARγ antagonist (2 mg/kg, i.p.), anti-granulocyte antibody (50 µL, i.p.) or L-NAME (70 mg/kg, i.p.) 1 hour before the treatment with vehicle or LYSO-7. One hour after administration of the Et/HCl solution, neutrophils were quantified in the blood and bone marrow, the gastric microcirculatory network was studied in situ by intravital microscopy, in the gastric tissue were quantified the percentage of injured area, MPO activity, PPARγ gene and protein expression, iNOS and eNOS protein expression, and catalase, SOD, GPx, GR and GST activity. One hour after indomethacin administration, gastric tissue was removed to verify the efficacy of LYSO-7 on inflammatory mediator secretion. Chronic ulcer assay induced by acetic acid was carried out in Balb/c WT or ANXA1-/-, applying 20µL of acetic acid in the subserosal layer of the stomach and 24 hours after induction, animals were treated during seven days, once a day, with LYSO-7 (50 mg/kg), bezafibrate (50 mg/kg) or vehicle. Assays were performed with macrophages recruited to the peritoneum by sodium thioglycollate (3%, i.p.) and neutrophils by oyster glycogen (1%, i.p.). Acute and chronic toxicological and mutagenicity assays were also conducted. The results obtained show that LYSO-7 treatment decrease the injured area, neutrophil influx and microcirculatory stasis evoked by Et/HCl administration. Protective effects were reversed in animals pretreated with GW9962, indicating the involvement of PPARγ. Neutrophil influx is a determinant of the gastric lesion, once the depletion of these cells decreased the gastric damage, indicating that in the neutrophil mobilization blockade from the bone marrow to blood and to injured tissue may be a gastroprotective mechanism of LYSO-7. The vascular stasis reversion in the microcirculation is mediated by NO, but not the neutrophil influx, since the pretreatment with L-NAME abolished the effects of LYSO-7 on blood flow. This effect was dependent on increase and decrease of eNOS and iNOS protein expression, respectively. LYSO-7 positively altered the activity of antioxidant enzymes in the gastric tissue. Furthermore, LYSO-7 reduced the injured area and the concentration of TNFα and increased IL-10 in the gastric tissue in the indomethacin-induced ulcer model. In the resolution of inflammation, LYSO-7 treatment decreased the percentage of the injured area, increased the neutrophils apoptosis and the efferocytosis of apoptotic neutrophils by peritoneal macrophages, inhibited the TNFα release and increased the secretion of IL-10, IL-1ß and VEGF in the supernatant of phagocytosis assay. The resolution of gastric lesions, as well as, the induction of phagocytosis by LYSO-7 was reduced in animals ANXA1-/-. This data shown the relation of PPARγ and ANXA1, as PPARγ expression is reduced in macrophages obtained from ANXA1-/- animals. Toxicological studies showed that LYSO-7 has low acute and chronic toxicity in vivo, and did not cause mutagenicity in bone marrow erythrocytes. The data obtained show that LYSO-7 acts as PPARγ in the modulation of gastric ulcer and modulate neutrophil migration and blood flow in the microcirculation. The transactivation and transrepression of eNOS and iNOS, respectively, blocking the neutrophil influx into the injury, antioxidant enzymes activation in the gastric epithelium and inhibition of inflammatory mediators release seem to be the mechanisms action of LYSO-7 in gastric cytoprotection. Additionally, LYSO-7 operates in the resolution of inflammation promoting downregulation in the secretion of inflammatory mediators and increases the neutrophil apoptosis and efferocytosis of apoptotic neutrophils

Effect of Lutein on L-NAME-Induced Hypertensive Rats

We investigated the antihypertensive effect of lutein on NG-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. Daily oral administration of L-NAME (40 mg/kg)-induced a rapid progressive increase in mean arterial pressure (MAP). L-NAME significantly increased MAP from the first week compared to that in the control and reached 193.3+/-9.6 mmHg at the end of treatment. MAP in the lutein groups was dose-dependently lower than that in the L-NAME group. Similar results were observed for systolic and diastolic blood pressure of L-NAME-induced hypertensive rats. The control group showed little change in heart rate for 3 weeks, whereas L-NAME significantly reduced heart rate from 434+/-26 to 376+/-33 beats/min. Lutein (2 mg/kg) significantly prevented the reduced heart rate induced by L-NAME. L-NAME caused hypertrophy of heart and kidney, and increased plasma lipid peroxidation four-fold but significantly reduced plasma nitrite and glutathione concentrations, which were significantly prevented by lutein in a dose-dependent manner. These findings suggest that lutein affords significant antihypertensive and antioxidant effects against L-NAME-induced hypertension in rats.

Protective effect of regular aerobic training on inflammatory and toxicity markers of lung tissue in L-NAME-induced hypertension.

Hypertension is a multi-factorial, life-threatening disease. The present study was designed to investigate protective effect of aerobic regular training on inflammatory and toxicity markers in lung tissue of male wistar rats exposed to chronic nitro-L-arginine-methyl ester(L-NAME)-induced hypertension. Thirty two adult male Wistar rats are randomly classified into 4 groups; aerobic training, L-NAME, saline and control groups. Hypertension was induced by administration of L-NAME (10 mg/kg) for 8 weeks and 6 sessions a week. Aerobic training was performed between 25 to 64 minutes and the speed 15 to 22 m/min for 8 weeks and 5 sessions a week. Chronically administration of L-NAME cause a significant increase in angiotensin converting enzyme (ACE), interleukin 6 (IL-6) levels, and a significant decrease in superoxide dismutase (SOD) and nitric oxide (NO) levels, as compared to saline and control groups. In contrast, aerobic training for 8 weeks caused a significant increase in SOD, NO and a significant decrease in IL-6 and protein carbonyl (PC), as compared to LNAME and saline groups. Our study suggests aerobic regular exercise provided significant protection against L-NAME-induced toxicity in lung tissue by up-regulation of antioxidant systems and down-regulation of the inflammatory and vasoconstrictor factors in hypertensive rats. These results suggest that aerobic regular exercise may be considered as a potentially useful strategy to limit toxicity in lung tissue.

Inhibition of nitric oxide synthesis for four days induces vascular abnormalities and myocardial infarct areas but not significant arterial hypertension / Inibição da síntese do óxido nítrico durante quatro dias induz anormalidades vasculares e áreas de infarto miocárdico, porém, não induz hipertensão arterial significativa

BACKGROUND: Nitric oxide is an endothelium vasorelaxing factor and at least in some cases is the main cause of arterial hypertension, which is one of the most important risk factors of cardiovascular diseases. In Brazil, cardiovascular diseases are the first cause of mortality, representing about 30% of the total deaths. The L-NAME (Nω-nitro-arginine-methyl-ester) blocks the nitric oxide synthesis necessary to maintain the normal arterial pressure. OBJECTIVE: To study lesions in myocardium due to the inhibition of nitric oxide synthesis during four days (via L-NAME oral administration, concentration: 75 mgs versus 100 mL-1). METHODS: Fourteen normotensive young adults Wistar rats were submitted, during four days, to L-NAME. Six rats were utilized as the Control Group. At day 4 of the experiment, the animals were anesthetized, weighed, and their thoraxes were opened, and the cardiotomy was performed. The hearts were weighed, fixed, and processed using routine methods, and they were sectioned in 3 µm and stained. RESULTS: Abnormalities were observed in the wall of arterial vessels of any dimension, as vascular damage with increasing wall thickness related mainly to proliferation of arterial smooth muscle cell in submitted animals. Proliferation of cells in the intimal layer and its thickening were also observed in small arterial vessels (arteriole). Infarct areas were present. CONCLUSIONS: The present data suggested that inhibition of nitric oxide synthesis for four days induces vascular abnormalities and myocardial infarct areas, but not arterial hypertension.

CONTEXTO: O óxido nítrico é um fator de relaxamento vascular e, pelo menos em certos casos, é a principal causa de hipertensão arterial no ser humano. A hipertensão arterial é um importante fator de risco de doenças cardiovasculares. No Brasil, as doenças cardiovasculares são a primeira causa de mortalidade, representando cerca de 30% do total de óbitos. O L-NAME (Nω-nitro-arginina-metil-éster, Sigma Chemical, St. Louis) bloqueia a síntese do óxido nítrico necessária para a manutenção da pressão arterial normal. OBJETIVO: Estudar as lesões miocárdicas ocorridas por razão da inibição da síntese do óxido nítrico durante quatro dias (por meio da administração oral de L-NAME em concentração de 75 mgs versus 100 mL-1). MÉTODOS:Quatorze ratos Wistar jovens normotensos adultos foram submetidos durante quatro dias ao L-NAME. Seis foram utilizados como Grupo Controle. Aos quatro dias de experimento, os animais foram anestesiados, pesados, os tórax foram abertos e a cardiomiotomia foi efetuada. Os corações foram pesados, fixados e processados usando métodos de rotina e cortados em 3 µm de espessura e corados. RESULTADOS: As anormalidades foram observadas nas paredes arteriais de vasos de todos os calibres, como, por exemplo, o aumento da parede arterial relacionada principalmente à proliferação das células musculares lisas dos animais submetidos ao bloqueio do óxido nítrico. Também foi identificada proliferação das células da túnica íntima e seu espessamento nos vasos arteriais de pequeno calibre (arteríolas). Áreas de infarto estavam presentes. CONCLUSÕES: Os resultados sugerem que a inibição do óxido nítrico durante quatro dias induz anormalidades vasculares e áreas de infarto do miocárdio, contudo, não induz hipertensão arterial.

L-arginine, a nitric oxide precursor, reduces dapsone-induced methemoglobinemia in rats

Dapsone use is frequently associated to hematological side effects such as methemoglobinemia and hemolytic anemia, which are related to N-hydroxylation mediated by the P450 enzyme system. The aim of the present study was to evaluate the influence of L-arginine supplementation, a precursor for the synthesis of nitric oxide, as single or multiple dose regimens on dapsone-induced methemoglobinemia. Male Wistar rats were treated with L-arginine at 5, 15, 30, 60 and 180 mg/kg doses (p.o., gavage) in single or multiple dose regimens 2 hours prior to dapsone administration (40 mg/kg, i.p.). The effect of the nitric oxide synthase inhibitor L-NAME was investigated by treatment with multiple doses of 30 mg/kg (p.o., gavage) 2 hours before dapsone administration. Blood samples were collected 2 hours after dapsone administration. Erythrocytic methemoglobin levels were assayed by spectrophotometry. The results showed that multiple dose supplementations with 5 and 15 mg/kg L-arginine reduced dapsone-induced methemoglobin levels. This effect is mediated by nitric oxide formation, since the reduction in methemoglobin levels by L-arginine is blocked by simultaneous administration with L-NAME, a nitric oxide synthase inhibitor.

O uso da dapsona é frequentemente associado a efeitos adversos hematológicos, como a metemoglobinemia e anemia hemolítica, ambos relacionados com a N-hidroxilação mediada pelo sistema P450. O objetivo do estudo foi avaliar a influência da suplementação de L-arginina, um precursor da síntese de óxido nítrico, administrado em regime de dose única ou múltipla na metemoglobinemia induzida pela dapsona. Ratos machos Wistar foram tratados com L-arginina (po, gavagem) em dose única ou múltipla de 5, 15, 30, 60 e 180 mg/kg 2 horas antes da administração de dapsona (40 mg/kg, ip). O efeito do L-NAME, um inibidor de óxido nítrico sintase (NOS), foi avaliado através do tratamento com doses múltiplas de 30 mg/kg. Amostras de sangue foram coletadas duas horas após a administração de dapsona. A concentração de metemoglobina eritrocitária foi analisada por espectrofotometria. Os resultados mostraram que a suplementação em dose múltipla de 5 e 15 mg/kg de L-arginina reduziu os níveis de metemoglobina induzida pela dapsona. Este efeito é mediado pela formação de óxido nítrico, uma vez que a redução nos níveis de metemoglobina pela L-arginina é bloqueada pela administração simultânea de L-NAME, um inibidor da óxido nítrico sintase.

Involvement of nitric oxide pathways in neurogenic pulmonary edema induced by vagotomy

OBJECTIVE: The objective of this study was to evaluate the involvement of peripheral nitric oxide (NO) in vagotomy-induced pulmonary edema by verifying whether the nitric oxide synthases (NOS), constitutive (cNOS) and inducible (iNOS), participate in this mechanism. INTRODUCTION: It has been proposed that vagotomy induces neurogenic pulmonary edema or intensifies the edema of other etiologies. METHODS: Control and vagotomized rats were pretreated with 0.3 mg/kg, 3.0 mg/kg or 39.0 mg/kg of L-NAME, or with 5.0 mg/kg, 10.0 mg/kg or 20.0 mg/kg of aminoguanidine. All animals were observed for 120 minutes. After the animals' death, the trachea was catheterized in order to observe tracheal fluid and to classify the severity of pulmonary edema. The lungs were removed and weighed to evaluate pulmonary weight gain and edema index. RESULTS: Vagotomy promoted pulmonary edema as edema was significantly higher than in the control. This effect was modified by treatment with L-NAME. The highest dose, 39.0 mg/kg, reduced the edema and prolonged the survival of the animals, while at the lowest dose, 0.3 mg/kg, the edema and reduced survival rates were maintained. Aminoguanidine, regardless of the dose inhibited the development of the edema. Its effect was similar to that observed when the highest dose of L-NAME was administered. It may be that the non-selective blockade of cNOS by the highest dose of L-NAME also inhibited the iNOS pathway. CONCLUSION: Our data suggest that iNOS could be directly involved in pulmonary edema induced by vagotomy and cNOS appears to participate as a protector mechanism.

Rosuvastatin prevents proteinuria and renal inflammation in nitric oxide-deficient rats

OBJECTIVE: The aim of the present study was to assess the effects of rosuvastatin on renal injury and inflammation in a model of nitric oxide deficiency. METHODS: Male Wistar rats were randomly divided into four groups (n = 10/group) and treated for 28 days with saline (CTRL); 30 mg/kg/day L-NAME (L-name); L-NAME and 20 mg/kg/day rosuvastatin (L-name+ROS-20); or L-NAME and 2 mg/kg/day rosuvastatin (L-name+ROS-2). Systolic blood pressure was measured by plethysmography in the central artery of the tail. The serum total cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatinine, nitric oxide, interleukin-6, and tumor necrosis factor alpha levels were analyzed. Urine samples were taken to measure the albumin: urinary creatinine ratio. Kidneys were sectioned and stained with hematoxylin/eosin and Masson's trichrome. Immunohistochemical analysis of the renal tissue was performed to detect macrophage infiltration of the glomeruli. RESULTS: The systolic blood pressure was elevated in the L-name but not the L-name+rosuvastatin-20 and L-name+rosuvastatin-2 groups. The L-name group had a significantly reduced nitric oxide level and an increased interleukin-6 and tumor necrosis factor alpha level, albumin: urinary creatinine ratio and number of macrophages in the renal glomeruli. Rosuvastatin increased the nitric oxide level in the L-name+rosuvastatin-2 group and reduced the interleukin-6 and tumor necrosis factor alpha levels, glomerular macrophage number and albumin:urinary creatinine ratio in the L-name+rosuvastatin-20 and L-name+rosuvastatin-2 groups. CONCLUSION: Rosuvastatin treatment reduced glomerular damage due to improvement in the inflammatory pattern independent of the systolic blood pressure and serum lipid level. These effects may lead to improvements in the treatment of kidney disease.

Chronic treatment with the nitric oxide synthase inhibitor, L-NAME, attenuates estradiol-mediated improvement of learning and memory in ovariectomized rats

INTRODUCTION: The role of ovarian hormones and nitric oxide in learning and memory has been widely investigated. OBJECTIVE: The present study was carried out to evaluate the effect of the nitric oxide synthase (NOS) inhibitor, N (G)-nitro-L-arginine methyl ester (L-NAME), on the ability of estradiol to improve learning in OVX rats using the Morris water maze. METHODS: Forty rats were divided into five groups: (1) ovariectomized (OVX), (2) ovariectomized-estradiol (OVX-Est), (3) ovariectomized-L-NAME 10 (OVX-LN 10), (4) ovariectomized-L-NAME 50 (OVX-LN 50) and (5) ovariectomized-estradiol-L-NAME 50 (OVX-Est-LN 50). The animals in the OVX-Est group were treated with a weekly injection of estradiol valerate (2 mg/kg; i.m.). The OVX-LN 10 and OVX-LN 50 groups were treated with daily injections of 10 and 50 mg/kg L-NAME (i.p.), respectively. The animals in the OVX-Est-LN 50 group received a weekly injection of estradiol valerate and a daily injection of 50 mg/kg L-NAME. After 8 weeks, all animals were tested in the Morris water maze. RESULTS: The animals in the OVX-Est group had a significantly lower latency in the maze than the OVX group (p<0.001). There was no significant difference in latency between the OVX-LN 10 and OVX-LN 50 groups in comparison with the OVX group. The latency in the OVX-Est-LN 50 group was significantly higher than that in the OVX-Est group (p<0.001). CONCLUSION: These results show that L-NAME treatment attenuated estradiol-mediated enhancement of spatial learning and memory in OVX rats, but it had no significant effect in OVX rats without estrogen, suggesting an interaction of nitric oxide and estradiol in these specific brain functions.

Liver lipid peroxidation and antioxidant capacity in cerulein-induced acute pancreatitis

The aim of this study was to evaluate the role of oxidative damage in pancreatitis-induced hepatic injury. Thirty-five rats were divided into five groups (each of 7 rats): control, cerulein (100 µg/kg body weight), cerulein and pentoxifylline (12 mg/kg body weight), cerulein plus L-NAME (10 mg/kg body weight) and cerulein plus L-arginine (160 mg/kg body weight). The degree of hepatic cell degeneration differed significantly between groups. Mean malondialdehyde levels were 7.00 ± 2.29, 20.89 ± 10.13, 11.52 ± 4.60, 18.69 ± 8.56, and 8.58 ± 3.68 nmol/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively. Mean catalase activity was 3.20 ± 0.83, 1.09 ± 0.35, 2.05 ± 0.91, 1.70 ± 0.60, and 2.85 ± 0.47 U/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively, and mean glutathione peroxidase activity was 0.72 ± 0.25, 0.33 ± 0.09, 0.37 ± 0.04, 0.34 ± 0.07 and 0.42 ± 0.1 U/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively. Cerulein-induced liver damage was accompanied by a significant increase in tissue malondialdehyde levels (P < 0.05) and a significant decrease in catalase (P < 0.05) and GPx activities (P < 0.05). L-arginine and pentoxifylline, but not L-NAME, protected against this damage. Oxidative injury plays an important role not only in the pathogenesis of AP but also in pancreatitis-induced hepatic damage.

Kainic Acid-induced Neuronal Death is Attenuated by Aminoguanidine but Aggravated by L-NAME in Mouse Hippocampus

Nitric oxide (NO) has both neuroprotective and neurotoxic effects depending on its concentration and the experimental model. We tested the effects of NG-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) inhibitor, and aminoguanidine, a selective inducible NOS (iNOS) inhibitor, on kainic acid (KA)-induced seizures and hippocampal CA3 neuronal death. L-NAME (50 mg/kg, i.p.) and/or aminoguanidine (200 mg/kg, i.p.) were administered 1 h prior to the intracerebroventricular (i.c.v.) injection of KA. Pretreatment with L-NAME significantly increased KA-induced CA3 neuronal death, iNOS expression, and activation of microglia. However, pretreatment with aminoguanidine significantly suppressed both the KA-induced and L-NAME-aggravated hippocampal CA3 neuronal death with concomitant decreases in iNOS expression and microglial activation. The protective effect of aminoguanidine was maintained for up to 2 weeks. Furthermore, iNOS knockout mice (iNOS-/-) were resistant to KA-induced neuronal death. The present study demonstrates that aminoguanidine attenuates KA-induced neuronal death, whereas L-NAME aggravates neuronal death, in the CA3 region of the hippocampus, suggesting that NOS isoforms play different roles in KA-induced excitotoxicity.