PI3K/Akt信号通路及内质网应激在肝纤维化大鼠肝细胞凋亡中的作用

目的观察磷脂酰肌醇-3激酶/蛋白激酶(PI3K/Akt)信号通路及葡萄糖调节蛋白78(GRP78)、生长停滞及DNA损伤基因(CHOP/GADD153)在四氯化碳(CCl4)诱导的肝纤维化中的表达并探讨其可能的作用。方法将30只SD大鼠随机分为正常组、肝纤维化模型(皮下注射40%CCl4橄榄油溶液)4及8周组。HE染色法观察肝组织病理形态学;用real-time PCR技术检测肝脏内GRP78及CHOP mRNA的表达;用Western blot检测肝脏内PI3K/Akt信号通路中Akt1、磷酸化Akt1及内质网应激相关蛋白GRP78及CHOP的表达;用原位末端转移酶标记(TUNEL)检测细胞凋亡。结果与正常组大鼠比较,肝纤维化模型4及8周组大鼠肝脏内GRP78及CHOP mRNA和蛋白表达均明显升高(P0.05),而肝脏内Akt1和磷酸化Akt1蛋白的表达则较正常大鼠显著降低(P0.05);与正常组大鼠比较,肝纤维化模型4及8周组大鼠肝细胞凋亡显著升高(P0.05)。结论 PI3K/Akt信号通路及内质网应激可能在肝纤维化大鼠肝细胞凋亡中发挥了重要作用。

Effect of PI3K/Akt signaling pathway and endoplasmicreticulum stress on apoptosis of hepatocytes in rats with hepatic fibrosis

Objective To observe the changes of PI3K/Akt signaling pathway and endoplasmic reticulum stress related protein GRP78 and CHOP in CCl4 induced liver fibrosis and to explore their effects on hepatic fibrosis.Methods Thirty SD rats were randomly divided into normal control group, 4 and 8 weeks liver fibrosis group (hypodermic injection of 40% CCl4).Pathological changes of liver tissue was observed by HE staining.The techniques of real-time PCR was applied to detect mRNA of GRP78 and CHOP in liver.Detected expression of Akt1, phospho-Akt1, GRP78 and CHOP protein by western blot.Meanwhile, the cell apoptosis in liver was detected by TUNEL.Results Compared with the normal control group, GRP78 and CHOP mRNA and protein in 4 and 8 weeks liver fibrosis group was increased(P<0.05), while expression of Akt1, phospho-Akt1 in 4 and 8 weeks liver fibrosis group was lower than that in normal control group(P<0.05).Compared with normal control group, the apoptosis of hepatocytes in 4 and 8 weeks liver fibrosis group was elevated (P<0.05).Conclusions PI3K/Akt signaling pathway and endoplasmic reticulum stress may play important roles in the induction of apoptosis of hepatocytes in rats with hepatic fibrosis.