缺血预处理减轻大鼠肝缺血再灌注损伤的免疫机制研究

目的探讨大鼠肝缺血再灌注损伤(HIRI)的免疫机制和缺血预处理(IPC)的保护作用。 方法80只大鼠被随机分为假手术组(A组)、肝门阻断20 min组(B组)、30 min组(C组)、40 min组(D组)以及肝门阻断30 min前预处理组(E组),每组再分为再灌注2 h亚组和24 h亚组,各8只。检测再灌注后2 h、24 h的血丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、白细胞介素10、12(IL-10、IL-12)以及外周血T淋巴细胞亚群的水平,观察再灌注后2 h、24 h时的存活率及肝脏病理情况。 结果随着肝门阻断时间的延长,ALT、AST显著升高,肝内炎症细胞浸润增加,24 h存活率逐渐降低。D组再灌注2 h时,CD8+ T淋巴细胞显著升高,CD4+/CD8+比值下降,调节性T淋巴细胞显著减少,血清IL-10显著降低,而IL-12水平显著升高。再灌注后24 h,B组大鼠各项指标逐步恢复至假手术组水平,而D组大鼠CD4+T淋巴细胞、CD4+/CD8+比值尤其是Treg显著升高,且IL-10水平显著升高,IL-12水平明显降低。与C组相比,E组阻断30 min后无一例死亡,再灌注2 h的ALT、AST水平显著降低,Treg和IL-10水平显著升高,IL-12水平明显降低,再灌注24 h后各项指标恢复并接近假手术组水平,肝脏病理损伤较轻。 结论肝缺血再灌注引起肝脏损伤甚至死亡,可能与诱导T淋巴细胞尤其是Treg和细胞因子的紊乱有关。缺血预处理可以增加再灌注早期的Treg细胞,有效纠正免疫紊乱,减轻损伤。

Ischemia preconditioning reducing hepatic ischemia reperfusion injury via ameliorating immune dysfunction in rats

ObjectiveTo probe the protective effect and immunologic mechanisms of ischemia preconditioning on rats hepatic ischemia reperfusion (HIR) injury. MethodsEighty rats were divided randomly into five groups: sham operation (A), 20 min hepatic ischemia (B), 30 min hepatic ischemia (C), 40 min hepatic ischemia (D), and ischemia preconditioning 30 min before hepatic ischemia (E). And there were two subgroups in each group: 2-hour (n=8) and 24-hour (n=8) reperfusion after ischemia, respectively. The 24 h survival rates after reperfusion were observed. The peripheral blood was collected for measuring the levels of ALT, AST, IL-10 and IL-12. T lymphocytes, in particular regulatory T cells, were measured by flow cytometry. Liver tissues were obtained for pathological examination. ResultsWith hepatic ischemic time prolonged, the serum levels of ALT and AST increased significantly, and more inflammatory cells infiltered in the liver. The 24-hour-reperfusion survival rates in 20 min, 30 min and 40 min hepatic ischemia groups were 100%, 62.5% and 37.5%, respectively. Two hours after reperfusion in group D, IL-12 level and the proportion of CD8+ T lymphocyte were increased, while IL-10 level and the proportion of CD4+/CD8+ and Treg cells were decreased significantly. Twenty four hours after reperfusion, parameters of group B were close to the levels of sham operation group. On the contrary, in group D, IL-10 level, CD4+T lymphocytes, Treg cells and CD4+/CD8+ were still increased significantly with IL-12 levels descended remarkably. Ischemia preconditioning effectively decreased ALT, AST serum level and severity of liver pathological injury after HIR, and resulted in the high level of survival rates. Furthermore, ischemia preconditioning induced Treg cells and IL-10 level increasing, and IL-12 decreasing 2 hours after reperfusion. However, all parameters in group E were close to level of sham operation group 24 hours after reperfusion. ConclusionsHIR can induce the dysfunction of T lymphocytes, in particular Treg cells and cytokines with liver injury, even death. Ischemia preconditioning can prevent HIR injury, increase Treg proportion in the early reperfusion and prevent immune dysfunction.