Résumé
Abstract Background Clinical reports associate kidneys from female donors with worse prognostic in male recipients. Brain Death (BD) produces immunological and hemodynamic disorders that affect organ viability. Following BD, female rats are associated with increased renal inflammation interrelated with female sex hormone reduction. Here, the aim was to investigate the effects of sex on BD-induced Acute Kidney Injury (AKI) using an Isolated Perfused rat Kidney (IPK) model. Methods Wistar rats, females, and males (8 weeks old), were maintained for 4h after BD. A left nephrectomy was performed and the kidney was preserved in a cold saline solution (30 min). IPK was performed under normothermic temperature (37°C) for 90 min using WME as perfusion solution. AKI was assessed by morphological analyses, staining of complement system components and inflammatory cell markers, perfusion flow, and creatinine clearance. Results BD-male kidneys had decreased perfusion flow on IPK, a phenomenon that was not observed in the kidneys of BD-females (p< 0.0001). BD-male kidneys presented greater proximal (p= 0.0311) and distal tubule (p= 0.0029) necrosis. However, BD-female kidneys presented higher expression of eNOS (p= 0.0060) and greater upregulation of inflammatory mediators, iNOS (p= 0.0051), and Caspase-3 (p= 0.0099). In addition, both sexes had increased complement system formation (C5b-9) (p=0.0005), glomerular edema (p= 0.0003), and nNOS (p= 0.0051). Conclusion The present data revealed an important sex difference in renal perfusion in the IPK model, evidenced by a pronounced reduction in perfusate flow and low eNOS expression in the BD-male group. Nonetheless, the upregulation of genes related to the proinflammatory cascade suggests a progressive inflammatory process in BD-female kidneys.
Résumé
A padronização da indução de estresse oxidativo com a mstura de Fenton em rim isolado perfundido de rato e a avaliação do efeito antioxidante das flores de Nelumbo nucifera em rim isolado de rato oxidativamente estressado são realizadas no presente estudo. Seis grupos de rim isolado perfundido de rato foram utilizados para o presente estudo. O grupo I de rins recebeu veículo. O grupo II de rins foi oxidativamente estressados com a mistura de Fenton. Os grupos III e IV de animais foram tratados com duas doses graduais de extrato após a administração da mistura de Fenton. Os grupos V e VI de rins foram perfundidos com duas doses graduais de extrato sem a mistura de Fenton. A mistura de Fenton causou estresse oxidativo com diferença significativa de malondialdeído (TBARS), glutationa reduzida (GSH), glutationa peroxidase (GPx), catalase, glutamato oxaloacetato transaminase (GOT) e glutamato piruvato transaminase (GPT) (p<0,05) em ratos doentes. No tratamento dos animais com extrato, o estresse oxidativo foi diminuído com aumento nos antioxidantes e as enzimas marcadoras mantiveram o nível normal. Este efeito do extrato foi dependente da dose. Em conclusão, a mistura de Fenton desenvolveu o estresse oxidativo em rim isolado perfundido de rato e o extrato das flores de Nelumbo nucifera apresenta atividade antioxidante no rim isolado perfundido oxidativamente estressado.
Standardization of induction of oxidative stress with Fenton mixture in isolated perfused rat kidney and evaluation of antioxidant effect of Nelumbo nucifera flowers in isolated oxidatively stressed rat kidney are carried out in present study. Six groups of isolated perfused rat kidney were used for the present study. Group I kidneys were received vehicle. Group II kidneys were oxidatively stressed with Fenton mixture. Group III and IV animals were treated with two graded doses of extract after the administration of Fenton mixture. Group V and VI kidneys were perfused with two graded doses of extract without Fenton mixture. Fenton mixture was found to cause oxidative stress with significant difference of malondialdehyde (TBARS), Reduced glutathione (GSH), Glutathione peroxidase (GPx), catalase, Glutamate Oxaloacetate Transaminase (GOT) and Glutamate Pyruvate Transaminase (GPT) (p<0.05) in diseased rats. On treating animals with extract, the oxidative stress was decreased with increase in antioxidants and the marker enzymes were found to maintain the normal level. This effect of extract was found to be dose dependent. In conclusion, Fenton mixture developed the oxidative stress in isolated perfused rat kidney and Nelumbo nucifera flowers extract exhibits antioxidant activity in that oxidatively stressed isolated perfused kidney.