Postconditioning effect in the hepatic ischemia and reperfusion in rats

Abstract

Purpose:To evaluate the effect of postconditioning protection in liver tissue of rats submitted to ischemia and reperfusion. Methods: 25 Wistar male rats were randomized in three groups: Group A (ischemia and reperfusion -I/R), with 10 rats, which was made ischemia by vascular clamp application in hepatic hilum for 30 minutes and reperfusion for 60 minutes by removal of the clamp; Group B (Postconditioning -IPo), with 10 rats, with same procedure plus postconditioning (3 cycles of reperfusion inserted by 3 cycles of ischemia, 30 seconds for each phase, between ischemia and reperfusion phases); and Group C (Sham), with 5 rats, which took place only laparotomy and manipulation of the hepatic hilum. Specimens were examined (histological evaluation) and dosage of serum AST and ALT was made. The statistical analysis was made with t Student test, with significant difference when p<0.05. Results: In the Sham group there was no histological or enzymatic changes; In group A the mean tissue lesion was 1.6 and in group B 1.1 (p=0.014). In group A the mean ALT level was 355U/l and in group B was 175.9U/l (p=0.016). The mean of AST was 828.8U/l in group A and 295.5U/l in group B (p=0.001). Conclusion: The postconditioning was able to minimize the severity of liver injury in rats submitted to ischemia and reperfusion. Key words: Ischemia. Reperfusion. Liver. Rats. RESUMO Objetivo:Avaliar o efeito do pós-condicionamento isquêmico na proteção tecidual hepática de ratos submetidos à isquemia e reperfusão. Métodos: Foram utilizados 25 ratos da linhagem Wistar provenientes do Biotério da Universidade Federal de Mato Grosso do Sul, distribuídos em três grupos: A) grupo isquemia/reperfusão (I/R) (10 ratos), em que foi realizada isquemia e reperfusão hepática pela aplicação e retirada de clampe do hilo hepático durante 30 e 60 minutos, respectivamente; B) grupo pós-condicionamento isquêmico (PoCI) (10 ratos), em que foi realizado procedimento semelhante ao anterior, exceto pela realização do pós-condicionamento isquêmico entre as fases de isquemia e reperfusão, consistindo na retirada e colocação do clampe do hilo hepático por 30 segundos cada fase, durante 3 ciclos; grupo C (Sham) (5 ratos), em que realizou-se apenas laparotomia e manipulação do hilo hepático. Foram analisados os espécimes (avaliação histológica), dosagem sorológica de AST e ALT. Resultados: No grupo Sham não se observou alterações histológicas nem enzimáticas; no grupo A a média de lesão tecidual foi 1,6 e no grupo B 1,1 (p=0,014). No grupo A a média de ALT foi 355U/l e no grupo B 175,9U/l (p=0,016). A média de AST foi de 582,8U/l no grupo A e 295,5U/l no grupo B (p=0,001). Conclusão: O pós-condicionamento isquêmico foi capaz de minimizar a intensidade das lesões hepáticas de ratos submetidos à isquemia e reperfusão. Descritores: Isquemia. Reperfusão. Fígado. Ratos.

Ischemic Postconditioning Assessment in the Liver of Rats Undergoing Mesenteric Ischemia and Reperfusion

“…The effectiveness of IPC in minimizing liver reperfusion injury had already been demonstrated by Santos et al [17] , through the evaluation of its effect directly on liver I/R, as opposed to this study, which analyzed its remote effect. That study showed the effectiveness of the method with three cycles of IPC lasting 30 seconds each, which corroborates the findings of this research, which also found better results with shorter cycles, although there was no statistically significant difference.…”

Ischemia and reperfusion of rat small intestine using pentoxyfilline and prostaglandin E1

“…To repair this special area it is mandatory a tissue reperfusion. If this subtle interruption occurs partially or in the whole small intestine, with a high intensity, many times it is not possible to maintain even the basal metabolism and, consequently, there is cell death and tissue necrosis [1][2][3][4] . The intestinal mucosa in the small intestine, it is the first area to be severely affected in cases of ischemia.…”

Current protective strategies in liver surgery

“…As with IPC, adenosine and nitric oxide play a pivotal role in ischaemic postconditioning. As in the case of IPC, ischaemic post-conditioning can also be achieved by a local postconditioning stimulus (direct IPost) [11,[42][43][44] or by a remote postconditioning stimulus (RIPost) [45] .…”

“…In animal models, there is experimental evidence that IPost protects against liver IR injury [42][43][44] . There are currently no randomized controlled trials of ischaemic postconditioning (direct or remote) in either liver resection or liver transplantation.…”