Histological analysis of the intestinal wall of newborn rats submitted to hypoxia and reoxygenation to evaluate the protective effect of N-Acetylcysteine.

PURPOSE: To evaluate the effect of N-Acetylcysteine (NAC) in newborn rats submitted to hypoxia and reoxygenation (H/R) conditions in an experimental model of necrotizing enterocolitis. METHODS: Eight pregnant rats and their 70 cubs were used (5 groups) and exposed to H/R conditions and received NAC at different times. The animals in the H/R groups were placed in a gas chamber (100% CO2) for 10 minutes and then reoxygenated for 10 minutes (100% O2), twice a day for the first three days of life, with a six-hour span between events. On the third day of life, the animals were anesthetized, laparotomized and the intestines were resected. RESULTS: The H/R and NAC groups showed changes in the intestinal wall in relation to the number, height and width of the villi when compared to the control group (p<0.0001), but with better preservation of structures in the NAC group. There were no differences between groups regarding the number (%) of mitoses. CONCLUSION: The administration of NAC decreased the lesions in the intestinal wall of rats submitted to H/R, therefore suggesting that this drug can be used to prevent the development of necrotizing enterocolitis in newborns.

Histological analysis of the intestinal wall of newborn rats submitted to hypoxia and reoxygenation to evaluate the protective effect of N-Acetylcysteine

Abstract Purpose To evaluate the effect of N-Acetylcysteine (NAC) in newborn rats submitted to hypoxia and reoxygenation (H/R) conditions in an experimental model of necrotizing enterocolitis. Methods Eight pregnant rats and their 70 cubs were used (5 groups) and exposed to H/R conditions and received NAC at different times. The animals in the H/R groups were placed in a gas chamber (100% CO2) for 10 minutes and then reoxygenated for 10 minutes (100% O2), twice a day for the first three days of life, with a six-hour span between events. On the third day of life, the animals were anesthetized, laparotomized and the intestines were resected. Results The H/R and NAC groups showed changes in the intestinal wall in relation to the number, height and width of the villi when compared to the control group (p<0.0001), but with better preservation of structures in the NAC group. There were no differences between groups regarding the number (%) of mitoses. Conclusion The administration of NAC decreased the lesions in the intestinal wall of rats submitted to H/R, therefore suggesting that this drug can be used to prevent the development of necrotizing enterocolitis in newborns.

Effect of folic acid in a modified experimental model of anorectal malformations adriamycin-induced in rats.

PURPOSE: To determine the effect of a single dose of adriamycin (ADR) to induce anorectal malformations (ARMs) and determine the effect of folic acid (FA) in this model. METHODS: Ten female Wistar rats were divided randomly in two groups. Group A - ADR; Group B - FA+ADR. Dams from group B received daily, since two weeks before the pregnancy to the end of pregnancy, FA (50mg/kg) by gavage. Dams from both groups received ADR (6mk/kg) by intraperitoneal injection on gestational day (GD) 8. Their fetuses were harvested by cesarean section on GD21 and were examined looking for ARMs. The thickness of anal stratified squamous epithelium (ASSE) and intestinal epithelium (IE) were analyzed. p≤0.05*. RESULTS: 81 fetuses were harvested. The number of fetuses; number of ARMs; mean (∆%) (± SD) were determined to be, respectively: ADR - 41[29;65%(±37%)] versus FA+ADR - 40[04;16%(±36%)] (p=0.05). AMRs were significantly lower in FA+ADR group than in ADR group (p=0.05). The thickness (µm) of ASSE (± SD) and IE (± SD) were measured, respectively: ADR - [25.98(±0.74) and 19.48(±1.68)] versus FA+ADR - [24.74(±0.91) and 24.80(±0.81)] (p<0.005). The thickness of IE was significantly enlarged when FA was given (p<0.005). CONCLUSIONS: Single dose of adriamycin on D8 was able to induce anorectal malformations. Folic acid reduces the number and enlarged the IE of ARMs ADR-induced.

Effect of folic acid in a modified experimental model of anorectal malformations adriamycin-induced in rats

PURPOSE: To determine the effect of a single dose of adriamycin (ADR) to induce anorectal malformations (ARMs) and determine the effect of folic acid (FA) in this model. METHODS: Ten female Wistar rats were divided randomly in two groups. Group A - ADR; Group B - FA+ADR. Dams from group B received daily, since two weeks before the pregnancy to the end of pregnancy, FA (50mg/kg) by gavage. Dams from both groups received ADR (6mk/kg) by intraperitoneal injection on gestational day (GD) 8. Their fetuses were harvested by cesarean section on GD21 and were examined looking for ARMs. The thickness of anal stratified squamous epithelium (ASSE) and intestinal epithelium (IE) were analyzed. p≤0.05*. RESULTS: 81 fetuses were harvested. The number of fetuses; number of ARMs; mean (∆%) (± SD) were determined to be, respectively: ADR - 41[29;65%(±37%)] versus FA+ADR - 40[04;16%(±36%)] (p=0.05). AMRs were significantly lower in FA+ADR group than in ADR group (p=0.05). The thickness (µm) of ASSE (± SD) and IE (± SD) were measured, respectively: ADR - [25.98(±0.74) and 19.48(±1.68)] versus FA+ADR - [24.74(±0.91) and 24.80(±0.81)] (p<0.005). The thickness of IE was significantly enlarged when FA was given (p<0.005). CONCLUSIONS: Single dose of adriamycin on D8 was able to induce anorectal malformations. Folic acid reduces the number and enlarged the IE of ARMs ADR-induced.

Ascorbic acid reduces gentamicin-induced nephrotoxicity in rats through the control of reactive oxygen species.

BACKGROUND & AIM: Oxidative stress has been implicated in the pathophysiology of many forms of acute renal failure. The aim was examine the effect of vitamin C on oxidative stress and its relationship with nitric oxide on gentamicin-induced nephrotoxicity in rats. METHODS: We utilized 32 Wistar rats allocated in four groups of eight animals each: control (CTL), vitamin C (VIT C), gentamicin (GENTA), and GENTA + VIT C; all groups were treated during seven days. RESULTS: Serum urea and creatinine, serum and renal tissue malondialdehyde, blood superoxide anion and hydrogen peroxide in GENTA were increased vs CTL and vs VIT C, and decreased in GENTA + VIT C vs GENTA (all P < 0.05). Serum nitric oxide increased in GENTA vs CTL and vs VIT C, and reduced in GENTA + VIT C vs GENTA (P < 0.001). Urinary nitric oxide was reduced in GENTA vs CTL and vs VIT C and increased in GENTA + VIT C vs GENTA (P < 0.001). Severe degeneration of proximal tubules was present in GENTA, but only mild lesions were observed in GENTA + VIT C. CONCLUSION: This study suggests that VIT C is a valuable tool to protect against GENTA-induced nephrotoxicity, by reducing reactive oxygen species and increasing the nitric oxide.

Efeitos hemodinâmicos da oclusão da aorta durante anestesia inalatória com isoflurano e sevoflurano: estudo experimental em cães / Hemodynamic effects of aortic occlusion during inhalational anesthesia with isoflurane and sevoflurane: experimental study in dogs

JUSTIFICATIVA E OBJETIVOS: A supressão do fluxo aórtico e sua posterior liberação em intervenções cirúrgicas da aorta ocasionam importantes distúrbios hemodinâmicos. O objetivo deste estudo foi avaliar essas alterações em cães anestesiados com isoflurano ou sevoflurano. MÉTODO: Foram estudados 41 cães, divididos em dois grupos segundo o anestésico empregado na manutenção com 1 CAM: GI (n = 21) isoflurano; GS (n = 20) sevoflurano. Foi realizada a oclusão aórtica por insuflação de balão intra-arterial infradiafragmático por 30 minutos. Os parâmetros hemodinâmicos foram observados nos momentos M1 (controle), M2 e M3, 15 e 30 minutos após a oclusão aórtica, M4 e M5, 15 e 30 minutos após a desinsuflação do balão. RESULTADOS: Durante a oclusão da aorta, observou-se aumento da pressão arterial média (PAM), da pressão venosa central (PVC), da pressão de artéria pulmonar (PAP), da pressão de capilar pulmonar (PCP) e da resistência vascular sistêmica (RVS) sem aumento da resistência vascular pulmonar (RVP) e do débito cardíaco (DC). O DC manteve-se mais estável com o isoflurano comparado com o sevoflurano, com o qual apresentou diminuição após a oclusão. A freqüência cardíaca teve diminuição inicial seguida de aumento durante a oclusão sendo em GS mais expressiva do que em GI, porém sem diferença significativa entre os grupos. O volume sistólico não teve grandes alterações; o trabalho sistólico dos ventrículos esquerdo e direito aumentou após a oclusão de forma semelhante nos dois grupos. Com a liberação do fluxo PAM, PVC, PAP, PCP e RVS diminuíram, a RVP aumentou nos dois grupos; o trabalho ventricular diminuiu abruptamente. CONCLUSÕES: O estudo demonstrou ser o isoflurano mais bem indicado nessas intervenções cirúrgicas por causar menores alterações hemodinâmicas.

[Hemodynamic effects of aortic occlusion during inhalational anesthesia with isoflurane and sevoflurane: experimental study in dogs]. / Efeitos hemodinâmicos da oclusão da aorta durante anestesia inalatória com isoflurano e sevoflurano: estudo experimental em cães.

BACKGROUND AND OBJECTIVES: Aortic flow suppression and release during aortic procedures promote major hemodynamic disorders. This study aimed at evaluating these disorders in dogs anesthetized with isoflurane or sevoflurane. METHODS: This study involved 41 dogs divided in two groups according to the anesthetic agent used for maintenance with 1 MAC: GI (n = 21) isoflurane; GS (n = 20) sevoflurane. Aorta was occluded by intra-arterial infra-diafragmatic cuff inflation for 30 minutes. Hemodynamic parameters were observed in moments M1 (control), M2 and M3, 15 and 30 minutes after aortic occlusion, M4 and M5, 15 and 30 minutes after cuff deflation. RESULTS: During aortic occlusion there has been increased mean blood pressure (MBP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP) and systemic vascular resistance (SVR), without increase in pulmonary vascular resistance (PVR) and cardiac output (CO). CO was more stable with isoflurane as compared to sevoflurane where it has decreased after occlusion. Heart rate has initially decreased followed by increase during occlusion, being more expressive in GS as compared to GI, however without statistically significant difference between groups. Systolic volume was not importantly changed; left and right ventricular function have similarly increased after occlusion for both groups. With flow release, MBP, CVP, PAP, PCWP and SVR have decreased, and PVR has increased for both groups; ventricular function has abruptly decreased. CONCLUSIONS: This study has shown that isoflurane is a better indication for such interventions for promoting less hemodynamic changes.