血红素氧合酶对大鼠肝脏缺血再灌注损伤细胞凋亡及相关基因的影响

Effect of heme oxygenase on apoptosis and apoptosis genes in hepatic ischemia reperfusion injury in rats

目的通过应用血红素氧合酶（HO）的诱导剂氯高血红素和抑制剂锌原卟啉（ZnPP），探讨HO对大鼠肝脏缺血再灌注（IR）细胞凋亡及其相关基因的影响。方法将96只Sprague—Dawley大鼠采用钳夹法制备肝脏IR模型，随机分为假手术组、IR组、氯高血红素组和ZnPP组，检测再灌注0、1．5、4h和8h各个时间点大鼠肝脏功能以及病理学改变，流式细胞法测定肝细胞凋亡率、TUNEL法观察再灌注后4h大鼠肝细胞的凋亡情况，Western blot法检测再灌注后8h Bcl-2和Caspase-3的表达。结果在IR组各时间点均可见ALT和AST增高，病理学检查可见肝细胞肿胀，肝窦变窄，嗜中性粒细胞浸润和片状坏死等变化，肝组织中细胞凋亡率明显升高，Bcl-2的表达减少，而Caspase-3的表达增加。在氯高血红素组再灌注后1．5、4h和8h ALT和AST值明显降低，肝脏病理学改善，凋亡细胞减少及细胞凋亡率降低，肝脏Bcl-2的表达增加，Caspase-3的表达减少。ZnPP组则显示与之相反的结果。结论HO在肝脏IR损伤中具有保护作用，这种保护作用可能与抑制细胞凋亡有关。

Objective To use heme oxygenase （HO） inducer hemin and a HO inhibitor zinc protoporphyrin （ZnPP） to investigate the effect of HO on apoptosis and apoptosis genes in hepatic ischemia reperfusion （IR） injury in rats. Methods Ninty-six Sprague-Dawley rats were randomly divided into four groups （24 rats in each）： a sham-operation group, an ischemia-reperfusion （IR） group, a hemin-IR group and a ZnPP-IR group. Liver functions, liver histology and hepatocellular apoptosis rates were observed at 0, 1.5, 4 and 8 hours after reperfusion. Hepatocellular apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling; expressions of Bcl-2 and caspase-3 were determined by Western blot. Results Compared with the sham-operation group, the levels of ALT and AST were increased in the IR group. In the IR group the histological changes found in the livers were swelling of hepatocytes, narrowing of hepatic sinusoids, inflammatory cell infiltration and necrosis of hepatocytes in some areas of the livers. In the IR group rate of hepatocellular apoptosis was increased at 0, 1.5, 4 and 8 hours after reperfusion; expression of Bcl-2 was decreased and the expression of caspase-3 was increased. In the hemin-IR group, the levels of ALT and AST were lower, the pathological changes were milder and the rate of hepatocellular apoptosis was lower at 0, 1.5, 4 and 8 hours in comparison to those of the IR group. The expression of Bcl-2 was higher and the expression of caspase-3 was lower in the hemin-IR group in comparison to those of the IR group. The results in the ZnPP-IR group were just the opposite to those of the hemin-IR group. Conclusion HO might play a protective role in hepatic IR injury in rats, and this effect may be related to the inhibition of hepatocellular apoptosis.