Melittin-induced metabolic changes on the Madin-Darby Bovine Kidney cell line / [Mudanças metabólicas induzidas por melitina em células da linhagem Madin-Darby Bovine Kidney]

In this study, the toxic effects of melittin on Madin-Darby Bovine Kidney cells (MDBK) were analyzed with respect to mitochondrial functionality by reduction of MTT and flow cytometry, apoptosis potential, necrosis, oxygen reactive species (ROS) production, lipid peroxidation, and DNA fragmentation using flow cytometry and cell membrane destabilization by confocal microscopy. The toxicity presented dose-dependent characteristics and mitochondrial activity was inhibited by up to 78.24 ±3.59% (P<0.01, n = 6) in MDBK cells exposed to melittin (10µg/mL). Flow cytometry analysis revealed that melittin at 2µg/mL had the highest necrosis rate (P<0.05) for the cells. The lipoperoxidation of the membranes was also higher at 2µg/mL of melittin (P<0.05), which was further confirmed by the microphotographs obtained by confocal microscopy. The highest ROS production occurred when the cells were exposed to 2.5µg/mL melittin (P<0.05), and this concentration also increased DNA fragmentation (P<0.05). There was a significative and positive correlation between the lipoperoxidation of membranes with ROS (R=0.4158), mitochondrial functionality (R=0.4149), and apoptosis (R=0.4978). Thus, the oxidative stress generated by melittin culminates in the elevation of intracellular ROS that initiates a cascade of toxic events in MDBK cells.(AU)

Neste estudo, os efeitos tóxicos da melitina em células Madin-Darby Bovine Kidney (MDBK) foram analisados quanto à funcionalidade mitocondrial, por redução de MTT e citometria de fluxo, potencial de apoptose, necrose, produção de espécies reativas de oxigênio (ROS), peroxidação lipídica e fragmentação de DNA, utilizando-se citometria de fluxo e desestabilização da membrana celular, por microscopia confocal. A toxicidade apresentou características dose-dependentes e a atividade mitocondrial foi inibida até 78,24±3,59% (P<0,01, n = 6) em células MDBK expostas à melitina (10µg/mL). Análises por citometria de fluxo revelaram que a melitina a 2µg/mL apresentou o maior índice necrótico celular (P<0,05). A maior lipoperoxidação de membranas também foi na concentração de 2µg/mL de melitina (P<0,05), o que foi posteriormente confirmado por microscopia confocal. A maior produção de ROS aconteceu quando as células foram expostas a 2,5µg/mL de melitina (P<0,05), e essa concentração também aumentou a fragmentação de DNA (P<0,05). Houve uma significativa correlação positiva entre a lipoperoxidação de membranas e a produção de ROS (R=0,4158), funcionalidade mitocondrial (R=0,4149) e apoptose (R=0,4978). Portanto, o estresse oxidativo gerado pela melitina culminou na elevação de ROS intracelular, que inicia uma cascata de eventos tóxicos nas células MDBK.(AU)

Passion fruit (Passiflora edulis) leaf extract modulates the oxidative metabolism of rat peritoneal neutrophils in a model of inflammation

This study was conducted to evaluate the effect of extracts of Passiflora edulis Sims leaves on the oxidative metabolism of rat peritoneal neutrophils using a model of acute inflammation. The extract was obtained by maceration in 70% ethanol, evaporation under reduced pressure and lyophilisation. Total phenolic content (TP) was determined by the Folin-Ciocalteu assay. The P. edulis extract, in different doses, was administered by gavage 1 h prior to inflammation induction by carrageenan (8 mg/kg, i.p.); five hours later, the neutrophils were obtained by intraperitoneal lavage. The tests performed in neutrophils were cytochrome C and chemiluminescence assay as well as myeloperoxidase (MPO), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities. The administration of the extract reduced the number of neutrophils recruited to the site of inflammation; however, the extract did not alter the activity of NADPH oxidase as well as SOD activity in these cells. The MPO and CAT activities in peritoneal neutrophils of rat treated with extract was lower than in the control group, and the GPx activity was increased. Based on the experimental model utilised, the anti-inflammatory potential of P. edulis leaf extract could be related to the presence of phenolic compounds in the extract.

Efeito pró-oxidante do hidroperóxido de urato sobre proteínas sensíveis às alterações redox: implicações na resposta inflamatória / Pro-oxidant effect of urate hydroperoxide on redoxsensitive proteins: implications on inflammatory reponse

O hidroperóxido de urato (HOOU) é o produto da oxidação do ácido úrico por peroxidases. Sua produção é favorecida durante a inflamação e hiperuricemia, uma vez que há grande quantidade de ácido úrico, peroxidases inflamatórias e superóxido. Neste sentido, o objetivo deste estudo foi avaliar o efeito do hidroperóxido de urato sobre proteínas sensíveis à modulação redox em um ambiente inflamatório asséptico e outro que imita infecção. Assim, nesta tese comparou-se a estrutura química do HOOU obtido fotoquimicamente daquele obtido através da catálise enzimática pela mieloperoxidase. A obtenção do HOOU por foto-oxidação permitiu o melhor isolamento do composto. Este oxidante foi capaz de reagir especificamente com os aminoácidos contendo enxofre (metionina e cisteína). Neste sentido, foi investigada sua reatividade com tiol-peroxidases detoxificadoras de peróxido, a peroxiredoxina 1 e 2 (Prx1 e Prx2). O HOOU apresentou cinética rápida de reação com a Prx1, k = 4,9 × 105 M-1s-1 e Prx2, k = 2,3 × 106 M-1s-1, o que as torna um provável alvo celular, além disso, foi capaz de oxidar a Prx2 de eritrócitos humanos, mostrando ser capaz de atravessar a membrana plasmática. Além das Prxs, a albumina do soro também desempenha papel importante na homeostase redox. O HOOU foi capaz de oxidar a albumina com constante de velocidade de 0,2 × 102 M-1s- 1. Outra tiol-proteína com importante função na homeostase e sinalização redox é a tioredoxina (Trx). A Trx foi oxidada pelo HOOU com constante de reação de 2,8 × 102 M-1s-1 e foi liberada juntamente com a Prx1 e Prx2 das células de macrófagos humanos (linhagem THP-1) quando estas células foram incubadas com HOOU. A liberação dessas proteínas é reconhecidamente um sinal de estresse celular. Assim o HOOU pode estar envolvido na exacerbação do estresse oxidativo em ambiente inflamatório. Quando neutrófilos (linhagem HL- 60) e macrófagos humanos (linhagem THP-1) foram incubados na presença de ácido úrico e Pseudomonas aeruginosa houve uma diminuição na produção de ácido hipocloroso (HOCl). Isto se deveu à competição entre ácido úrico e cloreto pela mieloperoxidase e resultou em menor atividade microbicida pelas células, demonstrando que a formação do HOOU não contribui e, ao contrário, prejudica a atividade microbicida das células inflamatórias. Dessa forma, a oxidação do ácido úrico e formação do hidroperóxido de urato tanto altera a atividade microbicida das células inflamtárias, quanto leva à oxidação de tiósproteínas importantes para manutenção da homeostase redox. Assim, o HOOU pode ser o responsável pelos efeitos pró-oxidantes e pró-inflamatórios do ácido úrico solúvel, e isso indica que o papel antioxidante do ácido úrico deve ser revisto em situações de inflamação.

Urate hydroperoxide (HOOU) is the product of the oxidation of uric acid by peroxidases. The formation of HOOU is favored during inflammation and in hyperuricemia, where there is plenty amount of uric acid, inflammatory peroxidases and superoxide. Therefore, the aim of the present study was to evaluate the effect of urate hydroperoxide on redox sensitive proteins in an inflammatory environment and another that mimics infection. In this thesis the chemical structure of the HOOU produced by photo-oxidation was compared to that obtained by myeloperoxidase catalysis. The chemical production of HOOU allowed a better purification of the compound. This oxidant was able to specifically react with sulfur containing amino acids (methionine and cysteine). In this sense, its reactivity with peroxiredoxins (Prx1 and Prx2) was investigated. HOOU reacted fast with Prx1 k = 4.9 × 105 M-1s-1 and Prx2 k = 2.3 × 106 M-1s-1. In addition, HOOU was able to oxidize Prx2 from intact erythrocytes at the same extend as does hydrogen peroxide. Albumin is an important thiol-containing protein to redox homeostasis in plasma. HOOU was able to oxidize albumin with a rate constant of 0.2 × 102 M-1s-1. Another protein with important function in redox homeostasis is thioredoxin (Trx). Trx was oxidized by HOOU with a rate constant of 2.8 × 102 M-1s-1 and was released together with Prx1 and Prx2 from human macrophages cells (THP-1 cell line) that were incubated with HOOU. The release of these proteins is a signal of cellular stress. Thus, HOOU may be involved in the exacerbation of oxidative stress in inflammatory environments. When neutrophil (HL-60 cell line) and macrophages (THP-1 cell line) were incubated with uric acid and Pseudomonas aeruginosa there was a decrease in hypochlorous acid (HOCl) production because of the competition between chloride and uric acid by myeloperoxidase. It decreased HOCl and impaired the microbicidal activity of the cells, showing that HOOU does not contribute in bacteria clearance. Therefore, the oxidation of uric acid to urate hydroperoxide impairs microbicidal activity and oxidizes thiol-proteins in inflammatory cells contributing to a pro-oxidant status. In this context, the antioxidant role of uric acid in inflammatory response should be reviwed.

Señalización de la angiotensina II, a través de la producción de radicales libres en estructuras del sistema nervioso: papel en el estres agudo y crónico / Angiotensin II signaling, through the production of free radicals in structures of the nervous system: role in acute and chronic stress

Existen evidencias que apoyan la participación de las especies reactivas de oxígeno en las cascadas de señalización y transducción intracelular de la angiotensina II. La ANG II es importante en el mantenimiento de la homeostasis corporal, regulando la presión arterial y el metabolismo de fluidos y electrolitos. Se sabe que en la periferia, la ANG II es capaz de estimular a la NAD(P)H oxidasa con la subsiguiente producción de ERO. El anión superóxido es metabolizado secuencialmente por las enzimas antioxidantes como la superóxido dismutasa, la catalasa y la glutatión peroxidasa. A su vez, las especies reactivas de oxígeno son capaces de activar a las proteínas kinasas activadas por mitógenos, las cuales se encuentran asociadas al crecimiento y la diferenciación celular. Se evaluó la posible participación de las especies reactivas de oxígeno en el mecanismo de señalización intracelular mediado por el receptorAT1en el hipotálamo, el órgano subfornicaly médula suprarrenal de la rata. Nuestros resultados demostraron que la estimulación del tejido nervioso con ANG II in vitroincrementó la actividad de la enzimas antioxidante. Al evaluar el papel del receptor AT1, la NAD(P)H oxidasa, el anión superóxido y la proteína kinasa C; así como la activación de las ERK1/2 en la señalización de la ANG II en el hipotálamo, OSF y MSR, demostramos que el bloqueo del receptor AT1con losartán, la interferencia del ensamblaje de la NAD(P)H oxidasa con apocinina, el secuestro de anión superóxido empleando un mimético de la SOD, tempol,y la inhibición de la PKC con cheleritrina, bloquearon completamente el efecto que produce la ANG II sobre las enzimas antioxidantes in vitro.Igualmente, la activación de la ERK1/2 inducida por la ANG II fue reducida por APO y LOS a nivel hipotalámico. Adicionalmente, el bloqueo del receptor AT2hipotalámico con PD123319, no bloqueo sino que mas bien potenció la respuesta de las enzimas antioxidantes y la activación de las ERK1/2 inducida por la ANG II, lo que desenmascaró el efecto contra regulatorio del receptor AT2sobre la acción de la ANG II mediada por el receptor AT1. Se sabe que durante el estrés el sistema renina angiotensina circulante y cerebral se encuentra estimulado, por lo tanto el incremento de la ANG II endógena debería desencadenar vías de señalización similares a las reportadas in vitro. Efectivamente, nuestros hallazgos demostraron que tanto,el estrés agudo inducido por la inmovilización forzada,como el estrés crónico en ratas espontáneamente hipertensas incrementaron la actividad de las enzimas antioxidantes en las tres estructuras cerebrales estudiadas. Este efecto es mediado por la vía del receptor AT1, la estimulación de la NAD(P)H oxidasa y la producción de anión superóxido ya que el tratamiento in vivo con LOS, APO y TEM fue capaz de bloquear completamente el incremento de la actividad de las enzimas antioxidantes inducidas por el estrés y por ende por la ANG II endógena.A nivel de la MSR demostramos, por primera vez, que la estimulación del receptor AT2 esta asociada a la estimulación de la NAD(P)H oxidasa, ya que la APOy el PD 123319 fueron capaces de bloquear el incremento de la actividad de las enzimas antioxidantes inducida por la ANG II. Demostrando así, que el receptor AT1en la MSR contrarregula la acción de la ANG II a través del receptor AT2.En conclusión, nuestros resultados indican que a nivel del sistema nervioso las especies reactivas de oxígeno participan en la cascada de señalización intracelular de la ANG II, y ejercen un importante papel en la respuesta al estrés y la hipertensión.

Melatonina, isoenzimas de glutationa S-transferases e estresse oxidante em pacu Piaractus mesopotamicus (Holmberg, 1887) / Melatonin, isoenzymes of glutathione S-transferases and oxidative stress in pacu Piaractus mesopotamicus (Holmberg, 1887)

O oxigênio é fundamental para os vertebrados. No entanto, variações dos níveis de oxigênio na água podem provocar estresse oxidante em peixes porque privação de oxigênio seguida de reoxigenação forma espécies reativas de oxigênio (ERO) em células. Níveis intracelulares de ERO aumentados favorecem que moléculas de proteínas, fosfolipídios e ácidos nucleicos sofram alterações, vindo a prejudicar muitas funções celulares. No Pantanal, habitat do pacu, o nível de oxigênio varia circadianamente na água das lagoas rasas que acabam isoladas dos rios na seca. O pacu evoluiu sob a pressão contínua da exposição aos efeitos prejudiciais das ERO causados pelos pulsos de inundação. A melatonina, uma indolamina produzida na glândula pineal, influencia os níveis de atividade de enzimas antioxidantes que reduzem ERO, além de ser capaz de doar elétrons ou captar radicais livres de forma não enzimática. Os níveis de melatonina no pacu são mais altos no verão e menores no inverno. Isoenzimas de glutationa S-transferases que conjugam o tripetídeo glutationa com o 4-hidroxinonenal, aldeído derivado da peroxidação de ácidos graxos por ERO, são importantes para evitar alteração funcional de proteínas por ligação do 4-hidroxinonenal à sua estrutura. Neste trabalho procuramos relação entre estresse oxidante, níveis de atividades de glutationa S-transferase e melatonina, para estabelecer se a melatonina ajudaria pacus a superar os efeitos deletérios das espécies reativas de oxigênio. Ensaiamos atividades de isoenzimas de glutationa S-transferases no citosol de fígado de pacus mantidos em normoxia, hipoxia, reoxigenação e hiperoxia no inverno e no verão. Medimos o efeito da malatonina in vitro e in vivo sobre as atividades de isoenzimas de glutationa S-transferase. Medimos os efeitos do estresse oxidante sobre a ligação do 4-hidroxinonenal com proteínas nos fígados de pacus tratados com melatonina. Somente as isoenzimas que conjugam 4-hidroxinonenal com glutationa...

Oxygen is vital for vertebrates. However, changes in the levels of dissolved oxygen in water might cause oxidative stress in fishes because the shortage of oxygen followed by reoxygenation originates reactive oxygen species (ROS) inside cells. Higher intracellular levels of ROS favor alterations of proteins, phospholipids and nucleic acid molecules, which result in impairment of many cell functions. In Pantanal, the pacu's habitat, circadian variation of the oxygen levels occurs in water of the shallow lagoons that ended up isolated from the rivers along the dry season. Pacu has evolved under the pressure of continuous exposition to harmful effects of ROS caused by the annual inundation pulses. Melatonin, an indolamine produced by the pineal gland, influences the levels of activity of antioxidant enzymes that reduce ROS, and is capable of donating electrons of scavenge free radicals non-enzymatically. Pacu's melatonin levels are higher during summer than in winter. Glutathione S-transferases isoenzymes that catalyze the conjugation of the tripeptide glutathione with 4-hydroxynonenal, an aldehyde derived from peroxidation of fat acids by ROS, are important to avoid functional alterations of proteins consequential to the binding of 4-hydroxynonenal to their structures. In the work, we searched for facts that linked oxidative stress, levels of activity of glutathione S-transferase and melatonin, in order to establish whether melatonin could help pacus to overcome the pernicious effects of reactive oxygen species. We carried out assays of glutathione S-transferases in liver cytosol of pacus kept under normoxia, hypoxia, reozygenation and hyperoxia, in the summer and in the winter. We measured the effect of melatonin in vitro and in vivo on isoenzymes of glutathione S-transferases. We measured the effects of oxidative stress on the binding of 4-hydroxynonenal to proteins in liver of pacu treated with melatonin. Only isoenzymes that conjugate 4-hydroxynonenal...

[Effects of tempol on in vitro development of mouse embryos under oxidative stress]

Etiologically, oxidative stress can be considered as one of the reasons for defective embryonic development which leads to developmental arrest due to necrosis or apoptosis. Under in vivo conditions, multiple mechanisms act to protect the embryo against reactive oxygen species [ROS], but under in vitro conditions most of these mechanisms are absent leading to higher levels of ROS in the culture medium. The objective of this study was to compare the antioxidant effects of Tempol, 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-l-oxyl, a permeable synthetic antioxidant, on mouse preimplantation embryonic development in vitro conditions in the presence or absence of oxidative stress. Mature oocytes from mouse were retrieved following ovarian stimulation by the administration of Pregnant Mare Serum Gonadotropin [PMSG] and hCG. Upon in vitro fertilization, the zygotes were cultured in different groups in HTF medium containing 4 mg/ml BSA. To study the effects of oxidative stress on embryo development, the zygotes were cultured for an hour in a medium containing different concentrations of H[2]O[2]. After washing, the zygotes were transferred to the culture plate. The zygotes were later placed in the media containing different concentrations of Tempol following their culture in 10 microM H[2]O[2] for one hour to study the effects of different concentrations of the substance in the absence of other oxidative stresses. The data were later compared and statistically analyzed. The pre-implantation embryonic development decreased significantly in the case group, compared to the control group after a short exposure to H[2]O[2], - the effect being more noticeable in higher concentrations. Tempol reduced the impairments resulting from the oxidative stress to some extent. Under in vitro conditions and a concentration of 0.5 microM, Tempol improved embryonic development quality, quantitatively and morphologically. Tempol increased the percentage of two-cell embryos from 91.78% in the control group to 96.99% [p < 0.05], blastocysts from 67.80% in the controls to 81.33% [p < 0.05] in the cases, and significantly decreased embryonic arrest from 32.19% in the controls to 18.67% in the cases [p < 0.05]. ROS has a major role in embryonic arrest, witnessed in embryo cultures in vitro conditions. The present study showed that supplementation of embryo cultures with Tempol improved the embryonic development. It seems that addition of permeable synthetic antioxidants, such as Tempol, to embryo cultures could protect embryos from oxidative damage and improve embryonic development

study of the effect of estrogen hormonal modulation on liver ischemic reperfusion in rats

Ischemia/reperfusion [I/R] injury of the liver impaired hepatic regeneration and predisposed to liver failure. The prime factors contributing to injury are decreased nitric oxide [NO] level which favor vasoconstriction, increased production of reactive oxygen species [ROS], increased level of adhesion molecules and leukostasis, which further impair the hepatic microcirculation in the early reperfusion phase. Heat shock protein 70 [HSP70] was shown to be induced by stress. Of the present work was to study the effect of estrogen hormonal modulation on hepatic injury during I/R model in male rats and to investigate the possible involvement of HSP 70 in the gender dimorphic response of the liver to this injury. Forty adult male albino rats were used in this work. They were divided into 5 groups [each of eight rats]; eight rats were taken as normal sham operated group.The remaining rats were subjected to total hepatic I/R. Each group received a specific treatment given intraperitoneally [ip] including: 17-beta estradiol [E[2]], raloxifene [Ral.] and genistein [Gen.] one hour before surgical procedure. The sham operated rats were injected with the veichle dimethyl sulfoxide solution. The I/R group was pretreated with the vehicle. Several parameters including: serum transaminases, HSP 70, ROS, Myeloperoxidase activity[MPO] and nitrite content were measured using standard assay procedures. I/R produced a significant increase in serum transaminases, MPO and ROS in liver tissue. HSP 70 was induced to a significantly higher level in I/R versus sham operated group but nitrite was significantly reduced in I/R versus sham operated rats. E[2+] I/R group had significantly lower transaminases, MPO and ROS versus I/R untreated group. A significantly higher nitrite level and HSP 70 was detected in liver tissue of E[2+] I/R versus I/R group. Ral.+I/R group showed significant lower serum transaminases, MPO and ROS in liver tissue versus I/R. Also Ral+ I/R showed significant higher nitrite and HSP70 versus I/R group. Gen.+I/R group showed decreased serum transaminases, lower MPO and ROS versus I/R. Nitrite level was significantly higher in Gen.+I/R versus I/R .Compared to E[2+] I/R or Ral.+I/R, geinstein pretreatment showed significantely lower HSP70. 17-beta estradiol pretreatment produced significant protection during hepatic I/R injury through multiple pathways. The protection was related to HSP70 induction, greater NO release, inhibition of ROS and MPO activity in liver tissue. Both the synthetic estrogen receptor modulator [SERM] raloxifene and the phytoestrogen genistein exerted significant estrogen agonist protective effects on the liver I/R injury. The mechanism of raloxifene protection was similar to estradiol, although protection due to genistein pretreatment did not involve HSP70 induction. Protection by genistein could be attributed to enhanced NO release and inhibition of ROS

Histological study of the protective effect of N-acetylcysteine on pancreatic acinar cells in experimentally induced acute pancreatitis in male albino rats

Despite extensive research efforts, there is a lack of specific medical/ pharmacological interventions of excellent clinical value in acute pancreatitis. The exact mechanisms by which diverse etiological factors induce an attack are unclear. Since reactive oxygen species [OR] are involved in acute pancreatitis, the present study was designed to assess the protective role of N-acetylcysteine in preventing the histological changes in pancreatic acinar cells, induced by L-arginine in albino rats. Twenty five male albino rats weighing 250-300g were included in this study. They were divided into four groups. Group I [10 rats]: the control group was further divided into: Group Ia: 5 animals received physiological saline injections i.p. Group Ib: 5 animals received N-acetylcysteine in a single dose of 50 mg/kg orally. Group II [5 rats]: in the treated group, acute pancreatitis was induced by two injections of 250 mg/100 g body weight of L-Arginine intraperitoneally in an 1-h interval. Group III [5 rats]: the animals were administered N-acetylcysteine in the same dose as that given to group Ib 1 hour prior to L-Arg administration. Group IV [5 rats]: the rats received the same dose of N-acetylcysteine 1h after L-Arg was given. All rats were sacrificed 24 h after the second L-Arg injection. Specimens from the pancreas of each animal were subjected to light microscopic examination using Haematoxylin and Eosin stain and ultrastructural examination. Histological results of group II [rats received L-Arginine] showed variable histological changes with different severity. Interlobular and interstitial tissue oedema, cellular infiltration and extravasation of blood appered in some sections. The peripheral fat cells were necrotic. Most lobules revealed loss of normal architecture with focal peripheral areas of acinar cell lysis. Some acinar cells showed cytoplasmic vacuolations and nuclear changes. Marked dilatation of rER, focal areas of rarefaction and depletion of zymogen granules were also noticed in ultrastructural examination. Pretreatment with N-acetylcysteine revealed marked protective effect on the histological changes of pancreatitis induced by L-arginine. This protection was less evident in group IV receiving N-acetylcysteine after administration of L-arginine and induction of pancreatitis. N-acetylcysteine proved to be of benefit in protection of the pancreas from the experimentally induced pancreatitis by L-arginine especially if administered before induction. Supplemental antioxidant therapy seems promising in the regulation of the progress of acute pancreatitis and it is recommended to be given to patients at an earlier stage or those at risk for the development of acute pancreatitis

Gene and aging

Collection of multiple processes that increase the chronological age of an organism leading to death is defined as aging, and even though important, it is poorly understood. Recent research has shown that aging is due to biochemical and genetic changes, in interaction with environmental effects, including diet and nutrition. Most knowledge on aging is based on genetic model system, but its molecular mechanisms are still not very clear. Discoveries in molecular biology have made way to look for candidate genes influencing lifespan. Furthermore, new investigations have stressed on the roles of mitochondria as the major generators and direct targets of reactive oxygen species. This paper reviews some recent literature on genes and aging in model system, then discusses the role of mitochondria and nutrients in human aging

Regulation of pro-inflammatory responses by lipoxygenases via intracellular reactive oxygen species in vitro and in vivo

Reactive oxygen species (ROS) performs a pivotal function as a signaling mediator in receptor-mediated signaling. However, the sources of ROS in this signaling have yet to be determined, but may include lipoxygenases (LOXs) and NADPH oxidase. The stimulation of lymphoid cells with TNF-alpha, IL-1beta, and LPS resulted in significant ROS production and NF-kappaB activation. Intriguingly, these responses were markedly abolished via treatment with the LOXs inhibitor nordihydroguaiaretic acid (NDGA). We further examined in vivo anti-inflammatory effects of NDGA in allergic airway inflammation. Both intraperitoneal and intravenous NDGA administration attenuated ovalbumin (OVA)-induced influx into the lungs of total leukocytes, as well as IL-4, IL-5, IL-13, and TNF-alpha levels. NDGA also significantly reduced serum levels of OVA-specific IgE and suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine. The results of our histological studies and flow cytometric analyses showed that NDGA inhibits OVA-induced lung inflammation and the infiltration of CD11b+ macrophages into the lung. Collectively, our findings indicate that LOXs performs an essential function in pro-inflammatory signaling via the regulation of ROS regulation, and also that the inhibition of LOXs activity may have therapeutic potential with regard to the treatment of allergic airway inflammation.

Reactividad vascular en anillos aórticos de rata: estudio comparativo en dos modelos de diabetes experimental / Vascular reactivity in aortic rings of rats: comparative study in two models of experimental diabetes

Los modelos experimentales para la diabetes de tipo I incluyen sustancias químicas (estreptozotocina o aloxano) y procedimientos quirúrgicos como la pancreatectomía. En estudios previos efectuados en anillos aórticos obtenidos de ratas diabéticas por estreptozotocina o pancratectomía, se ha observado una alteración en la respuesta vascular.

A comparison of the protective effects of systemic administration of a pro-glutathione drug and a Src-PTK inhibitor against noise-induced hearing loss.

Both the antioxidant, n-l-acetyl cysteine (L-NAC) and the Src inhibitor, KX1-004, have been used to protect the cochlea from hazardous noise. To date, KX1-004 has only been used locally on the round window. In the current study, the two drugs were administered systemically. LNAC was delivered intraperitoneally at a dose of 325 mg/kg while KX1-004 was administered subcutaneously at a dose of 50 mg/kg. The noise exposure consisted of a 4 kHz octave band of noise at 100 dB SPL for 6 hours/day for 4 days. The drugs were administered once each day, 30 minutes prior to the onset of the noise exposure. The animals' hearing was estimated using the evoked response records from surgically-implanted chronic electrodes in the inferior colliculi. Animals treated with LNAC and KX1-004 had from 10 to 20 dB less temporary threshold shift at day 1 and an average 10 dB less permanent threshold shift by day 21 when compared to control saline treated animals. There were no significant side effects (i.e.: appetite loss, weight loss, lethargy, etc.) related to either of the drug treatments. KX1-004 produced at least as much protection as L-NAC, but at a significantly lower concentration.

Blood superoxide dismutase and catalase activities in women affected with breast cancer

Experimental and epidemiological evidences implicate the involvement of oxygen derived radicals in the pathogenesis of cancer development. Oxygen derived radicals are able to cause damage to membranes, mitochondria and macromolecules including proteins, lipids and DNA. Accumulation of DNA damages has been suggested to contribute to carcinogenesis. It would, therefore, be advantageous to pinpoint the effects of oxygen derived radicals in cancer development. We investigated superoxide dismutase [SOD] and Catalase [CAT] activities in the whole blood of 50 breast cancer [BC] patients and 50 healthy and age matched women. The rate of SOD and CAT activities in BC patients was significantly lower [P<0.001] than controls. No effect of stage on SOD and CAT activities was observed. The results of our study have shown a higher reactive oxygen species [ROS] production and decreased SOD and CAT activities, which support the oxidative stress hypothesis in carcinogenesis. The relative lower SOD and CAT activities may not be adequate to detoxify high levels of H[2]O[2] into H[2]O leading to the formation of the most dangerous OH radical. Therefore, administration of antioxidants may be helpful in the management of BC patients. However, elaborate clinical studies are required to evaluate the role of such antioxidant enzymes [AOE] in BC management

Free radicals and antioxidants in human health: current status and future prospects.

Free radicals and related species have attracted a great deal of attention in recent years. They are mainly derived from oxygen (reactive oxygen species/ROS) and nitrogen (reactive nitrogen species/RNS), and are generated in our body by various endogenous systems, exposure to different physicochemical conditions or pathophysiological states. Free radicals can adversely alter lipids, proteins and DNA and have been implicated in aging and a number of human diseases. Lipids are highly prone to free radical damage resulting in lipid peroxidation that can lead to adverse alterations. Free radical damage to protein can result in loss of enzyme activity. Damage caused to DNA, can result in mutagenesis and carcinogenesis. Redox signaling is a major area of free radical research that is attracting attention. Nature has endowed us with protective antioxidant mechanisms- superoxide dismutase (SOD), catalase, glutathione, glutathione peroxidases and reductase, vitamin E (tocopherols and tocotrienols), vitamin C etc., apart from many dietary components. There are epidemiological evidences correlating higher intake of components/ foods with antioxidant abilities to lower incidence of various human morbidities or mortalities. Current research reveals the different potential applications of antioxidant/free radical manipulations in prevention or control of disease. Natural products from dietary components such as Indian spices and medicinal plants are known to possess antioxidant activity. Newer and future approaches include gene therapy to produce more antioxidants in the body, genetically engineered plant products with higher level of antioxidants, synthetic antioxidant enzymes (SOD mimics), novel biomolecules and the use of functional foods enriched with antioxidants.

Reactive oxygen species inactivation improves pancreatic capillary blood flow in caerulein-induced pancreatitis in rats

Purpose: Reactive oxygen species (ROS) inactivation was studied to determine alterations in the pancreatic capillary blood flow (PCBF) during caerulein-induced pancreatitis in rats. Methods: A laser-Doppler flowmeter to measure PCBF and N-t-Butyl-Phenylnitrone (PBN) compound to inactivate ROS were used. Forty rats were divided in groups: 1) control; 2) caerulein; 3) PBN; 4) caerulein+PBN. Serem biochemistry and histopathological analyses were performed. Results: PCBF measured a mean of 109.08 ± 14.54 percent, 68.24 t 10.47 percent, 102.18 ± 10.23 percent and 87.73 ± 18.72 percent in groups 1, 2, 3 and 4, respectively. PCBF in groups 2 and 4 decreased 31.75 ± 16.79 percent and 12.26 ± 15.24 percent, respectively. Serum amylase was 1323.70 ± 239.10 U/l, 2184.60 ± 700.46 U/1, 1379.80 t 265.72 U/1 and 1622.10 ± 314.60 U/1 in groups 1, 2, 3 and 4, respectively. There was a significant difference in the PCBF and serem amylase when compared groups 2 and 4. Cytoplasmatic vacuolation was present in groups 2 and 4. Otherwise, no qualitative changes were seen. Conclusion: ROS inactivation improves PCBF and minimizes the serem amylase increase during caerulein-induced pancreatitis. ROS effect may be one of the leading causative events in this model of acute pancreatitis.

Involvement of reactive oxygen species in gastric ulceration: protection by melatonin.

Uncontrolled hydrochloric acid secretion and ulceration in the stomach due to various factors are serious global problems today. Although the mechanism of acid secretion from the parietal cell is now fairly known, the mechanism of gastric ulceration is still not clear today. Among various causes of gastric ulceration, lesions caused by stress, alcohol consumption, Helicobacter pylori infection and use of nonsteroidal antiinflammatory drugs have been shown to be mediated largely through the generation of reactive oxygen species especially hydroxyl radical (*OH). A number of excellent drugs have been proved useful in controlling hyperacidity and ulceration but their long term uses are not devoid of disturbing side-effects. Hence, the search is still on to find out a compound possessing antisecretory, antiulcer and antioxidant properties which will serve as a powerful therapeutic agent to cure gastric hyperacidity and ulcer. This article describes the role of reactive oxygen species in gastric ulceration, drugs controlling them with their merits and demerits and, the role of melatonin, a pineal hormone in protecting the gastric lesions with a final commentary on how melatonin research with respect to gastric pathophysiology can be taken forward with a view to projecting this indole as a promising therapeutic agent to control gastric ulceration in humans.