钴-原卟啉诱导HO-1过表达在小鼠肝缺血再灌注损伤中的抗凋亡作用研究

Anti-apoptotic effects of cobalt proporphyrin-induced overexpression of heme oxygenase-1 in a mouse ;model of liver ischemia-reperfusion injury

目的：探讨血红素氧化酶（ HO-1）在小鼠肝脏缺血再灌注损伤中的抗凋亡作用及机制。方法在小鼠肝 AML12细胞中转染 HO-1 siRNA 后建立缺氧/复氧模型,用 real-time PCR 和Western blot测定细胞水平上HO-1、Bcl2、caspase-3的变化。建立小鼠肝脏热缺血再灌注模型,进行钴-原卟啉（ CoPP）、CoPP＋锌-原卟啉（ ZnPP）、ZnPP预处理,检测血清谷草转氨酶（ AST）、谷丙转氨酶（ALT）变化,观察肝组织光镜下的改变,免疫组化检测caspase-3,Western blot分析HO-1、Bcl2蛋白水平,Tunel法观察检测肝细胞凋亡情况。结果在AML12细胞转染HO-1 siRNA后,HO-1、Bcl2的表达较缺氧/复氧组明显减少,而促凋亡蛋白caspase-3表达量增多。 CoPP预处理组较缺血再灌注损伤组的AST、ALT水平明显降低,差异有统计学意义（P〈0.05）；光镜下细胞损伤程度减轻,caspase-3阳性细胞数减少,Tunel染色凋亡细胞显著减少呈散在分布（P〈0.05）,HO-1、Bcl2的蛋白表达量增多；ZnPP加入后上述的保护作用受到了抑制。结论 HO-1在体外缺氧/复氧模型中可产生抗凋亡作用, CoPP可上调HO-1表达并在小鼠肝缺血再灌注损伤中起到抗凋亡保护作用。

Objective To investigate the anti-apoptosis effects of heme oxygenase-1 （HO-1） in a mouse model of liver ischemia-reperfusion （ IR ） injury and to analyze the possible mechanisms . Methods A cell model of hypoxia/reoxygenation injury was established after transfecting mouse liver AML12 cells with HO-1 small interfering RNA （ siRNA） . Real-time PCR and Western blot assay were performed to detect the changes of HO-1, B-cell lymphoma 2 （Bcl2） and caspase-3 at the cellular level. The mouse models of liver ischemia-reperfusion injury were established with/without pretreatments with cobalt proporphyrin （CoPP）, CoPP＋znic proporphyrin （ ZnPP） and/or ZnPP. The levels of aspartate transaminase （ AST） and alanine transaminase （ ALT） in serum samples were measured. Immunohistochemistry was used to analyze the chan-ges of caspase-3. Western blot assay was used to detect the expression of HO-1 and Bcl2 at protein level. The pathological changes of liver tissues were observed under light microscope. The apoptosis of hepatocytes was observed by using Tunel assay. Results Decreased expression of HO-1 and Bcl2 and increased expres-sion of caspase-3 were observed in the model of hypoxia/reoxygenation injury by pre-transfecting the AML12 cells with HO-1 siRNA. Compared with the IR injury group, the CoPP pretreatment group showed lower lev-els of AST and ALT （P〈0. 05） and alleviated pathological damages in liver tissues. Moreover, the expres-sion of caspase-3 was inhibited, but the expression of HO-1 and Bcl2 were enhanced. Less apoptotic cells was detected by the Tunel assay （P〈0. 05）. However, these protective effects could be suppressed by adding ZnPP. Conclusion HO-1 has anti-apoptotic effects in the in vitro model of hypoxia/reoxygenation. CoPP can upregulate the expression of HO-1 and play the role of anti-apoptosis in a mouse model of liver is-chemia-reperfusion injury.