干扰素-α通过PD-1/PD-L1途径减轻HBV感染引起的肝组织损伤和肝纤维化

IFN-α Reduce liver tissue damage and fibrosis caused by HBV infection through PD-1/PD-L1 pathway

目的:探讨干扰素-α(IFN-α)对乙型肝炎病毒(HBV)感染引起的肝组织损伤和肝纤维化的作用及机制。方法:将BALB/c小鼠随机分为对照组、模型组与IFN-α组,每组小鼠各15只。经尾静脉高压快速注射pAAV/HBV1.2制备HBV感染小鼠模型,IFN-α组小鼠在此基础上注射pKCMvint.IFN-α。于模型构建4周后,观察小鼠一般情况,ELISA法测定HBV血清学指标、肝功能指标及IFN-α水平,qPCR技术测定血清HBV DNA复制水平,HE染色法观察肝组织形态学改变,Masson染色观察肝组织纤维化程度,免疫组化染色法、蛋白免疫印迹法及RT-PCR技术测定肝组织PD-1和PD-L1表达。结果:与模型组比较,IFN-α组小鼠肝细胞损伤明显减轻,仅有少量炎症浸润,肝组织内纤维化染色减少。IFN-α组小鼠血清乙型肝炎e抗原(HBeAg)、乙型肝炎表面抗原(HBsAg)及HBV DNA水平均显著低于模型组(P<0.05)。模型组小鼠血清谷草转氨酶(AST)和谷丙转氨酶(ALT)水平显著高于对照组小鼠(P<0.05);IFN-α组小鼠血清IFN-α水平显著高于模型组,AST和ALT水平显著低于模型组(P<0.05)。模型组小鼠肝组织内PD-1和PD-L1蛋白及mRNA水平显著高于对照组小鼠,IFN-α组小鼠上述指标水平则显著低于模型组小鼠(P<0.05)。结论:IFN-α可减轻HBV引起的肝组织损伤和肝纤维化,其机制可能通过PD-1/PD-L1途径阻止HBV DNA链延伸,进而终止病毒复制。

Objective:To explore the effect and mechanism of interferoN-α(IFN-α)on liver tissue injury and liver fibrosis caused by hepatitis B virus(HBV)infection.Methods:BALB/c mice were randomly divided into control group,model group and IFN-αgroup with 15 mice in each group.The mouse model of HBV infection was made by rapid injection of pAAV/HBV1.2 through tail vein,and the IFN-αgroup was injected with pKCMvint.IFN-αon this basis.The general condition of mice was observed.Four weeks after the model was established,HBV serological indexes,liver function indexes and IFN-αlevel were measured by ELISA,HBV DNA replication level in serum was measured by qPCR,morphological changes of liver tissue were observed by HE staining,fibrosis degree of liver tissue was observed by Masson staining,and expressions of PD-1 and PD-L1 in liver tissue were measured by immunohistochemical staining,western blotting and RT-PCR.Results:Compared with the model group,the damage of liver cells in IFN-αgroup was significantly reduced,with only a small amount of inflammation infiltration and less fibrosis staining in liver tissue.The levels of serum hepatitis Be antigen(HBeAg),hepatitis B surface antigen(HBsAg)and HBV DNA in IFN-αgroup were significantly lower than those in model group(P<0.05).Serum aspartate aminotransferase(AST)and alanine transaminase(ALT)levels in model mice were significantly higher than those in control group(P<0.05).Serum IFN-αlevels in IFN-αgroup were significantly higher than those in model group,while AST and ALT levels were significantly lower than those in model group(P<0.05).The protein and mRNA levels of PD-1 and PD-L1 in liver tissue of model mice were significantly higher than those of control group,while those of IFN-αgroup were significantly lower than those of model group(P<0.05).Conclusion:IFN-αmay inhibit HBV DNA strand extension through the PD-1/PD-L1 pathway,which can reduce HBV induced liver tissue injury and liver fibrosis,thus terminating viral replication.