HNF4α在胎肝干细胞促肝组织损伤修复中的作用

目的探讨肝细胞核因子(HNF)4α在胎肝干细胞促大鼠肝组织损伤修复中的作用。方法胶原酶结合机械消化法制备14 d胎龄大鼠胎肝干细胞悬液并进行体外长期培养。采用四氯化碳制作SD大鼠急性化学性肝损伤模型,造模成功后将肝损伤大鼠随机分为移植组(20只)和对照组(20只),移植组将胎肝干细胞经门静脉移植至大鼠肝脏,对照组注射等容计量的生理盐水,分别于注射前6 h,注射后1,3,5周检测大鼠血清谷氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST),并检查肝组织病理学变化,观察肝脏修复情况。采用免疫组化及Western-blot方法检测肝脏治疗前后HNF4α表达情况。结果对照组大鼠肝功能改善缓慢,ALT,AST明显高于移植组(P0.05),移植组大鼠损伤的肝组织逐渐修复,肝功能恢复正常。第5周移植组大鼠术后存活率显著高于对照组(P=0.002)。肝组织损伤后,HNF4α在肝组织的表达明显升高;随着肝组织的逐渐修复,HNF4α表达逐渐下降。western-blot及免疫组化检测亦证实此结果。结论HNF4α在肝脏损伤初期起保护作用。可能系通过促进胎肝干细胞向正常肝细胞分化增殖,并迁移至损坏的肝小叶从而替代损伤的肝实质,从而提高肝损伤后的恢复能力。

Study on the repatarive effect of HNF4&alpha|in embryonic hepatic stem cells on acute hepatic injury

Objective: To investigate the reparative effect of HNF4α embryonic hepatic stem cells on acute hepatic injury. 
Methods: Suspension of ED 14 Fischer (F) 344 rat embryonic hepatic stem cells was prepared by collagenase digestion and mechanical disaggregation and maintained by long-term culture in vitro. Healthy SD female rats were randomly divided into transplantation group (TP group, n=20) and control group (n=20). The experimental acute hepatic injury was induced by CCl4-lavage. Suspension of embryonic hepatic stem cells was transplanted into injured livers of rats in transplantation group via portal vein while saline of equal volume was used in control group. The levels of ALT and AST in the serum and histopathological injury of hepatic tissues were analyzed 6 h before, and 1w, 3w and 5w after injection. Evaluation of HNF4α protein expression in rat livers by immunohistochemistry and Western blot was performed before and after treatment.
Results: The liver function of control group was slow recovery, as evidenced by significantly increased ALT and AST in serum（P＜0.05）. By contrast, the injured hepatic tissues were markedly repaired in TP group, and liver function gradually returned to normal level. The survival rate of TP group at 5 weeks was significantly higher than that of control group (P=0.002). After liver injury, expression of HNF4α in the injured liver tissue notably increased. And then, in accordance with the gradual restoration of liver tissue, HNF4α expression was slowly decreased.
Conclusions: HNF4α plays a protective effect in the early stage of hepatic injury after liver transplantation, and it could probably act through promoting the restoration of acute hepatic injury by facilitating the differentiation, proliferation, and migration to damaged hepatic lobule of embryonic hepatic stem cell.