两种不同病毒载体携带靶向大鼠金属蛋白酶组织抑制因子(TIMP)-1小干扰RNA抗肝纤维化作用的比较

摘要

Objective To construct recombinant adeno-associated virus and lentivirus carrying siRNA of TIMP-1 and to investigate their antifibrotic effects on CCl4-induced liver fibrosis in rats.Methods One pair of siRNA which could effectively inhibit expression of the TIMP-1 gene in HSC-T6 was screened and cloned into AAV vector and lentiviral vector to construct the recombinant AAV/siRNA-TIMP-1 and Lenti/siRNA-TIMP-1.AAV/EGFP and Lenti/EGFP as negative control were also obtained.Fifty-eight male Wistar rats were randomly divided into six groups:control group (n =8),CCl4 group,AAV/EGFP,Lenti/EGFP,AAV/siRNA-TIMP-1 and Lenti/siRNA-TIMP-1 groups (all n =10).After the administration of CCl4 for four weeks,liver samples were collected for the immunohistochemical staining and detection of TIMP-1 expression.Results Livers from the control rats showed normal lobular structure around vessels (HE and Masson staining).In contrast,livers from the model,AAV/EGFP and Lenti/EGFP groups showed severe fibrosis,including septal fibrosis,extensive bridging,and fatty degeneration.The expressions of TIMP-1 mRNA and protein were also elevated in the livers from these groups.Compared with the fibrosis model group,the AAV/siRNA-TIMP-1 and Lenti/siRNA-TIMP-1 groups showed good preservation of liver lobular architecture and only mild bridging fibrosis,accompanied by decreased expression of TIMP-1 mRNA and protein.Semi-quantitative analysis of the fibrosis stage indicated that most rats in the model,AAV/EGFP and Lenti/EGFP groups were of S3 and S4 (80％),while 20％ of the rats were of S5.In contrast,most rats (90％) in the AAV/siRNA-TIMP-1 and Lenti/siRNA-TIMP-1 groups were of stages S2 and S3,with only one rat of S4.There was no significant difference between these recombinant virus therapy groups.Conclusions Both AAV/siRNA-TIMP-1 and Lenti/siRNA-TIMP-1 can suppress the expression of TIMP-1 in rat fibrotic liver,playing an effective antifibrotic role in the rat liver.%目的 观察以腺相关病毒(AAV)及慢病毒(Lentivirus)为载体含有针对大鼠金属蛋白酶组织抑制因子(TIMP)-1具有较强抑制作用的小干扰RNA(siRNA)对四氯化碳(CCl4)诱导的大鼠肝纤维化模型的干预作用.方法 挑选针对大鼠TIMP-1基因具有较强抑制作用的siRNA序列,在体外构建为短发夹表达载体后,将其包装为重组AAV/siRNA-TIMP-1和Lenti/siRNA-TIMP-1,同时包装对照病毒AAV/EGFP和Lenti/EGFP.将Wistar大鼠分为对照组、CC14模型组、AAV/EGFP组、Lenti/EGFP组、AAV/siRNA-TIMP-1和Lenti/siRNA-TIMP-1组,观察CCl4造模4周后,经H&E及Masson染色评价各组动物的肝纤维化状况,经荧光定量RCR及Western blot方法检测TIMP-1的表达抑制情况.结果 H&E及Masson染色证实,与对照组相比,CCl4模型组、AAV/EGFP组、Lenti/EGFP组肝脏胶原纤维明显增加,纤维化评分多为3-4级,同时肝脏TIMP-1的转录与蛋白表达水平均明显上升；而AAV/siRNA-TIMP-1和Lenti/siRNA-TIMP-1组肝纤维化程度明显减轻,纤维化评分多为2-3级,伴随肝脏TIMP-1的转录与蛋白表达水平均显著抑制.AAV/siRNA-TIMP-1和Lenti/siRNA-TIMP-1组在组织学表现及TIMP-1基因的转录与表达水平上无统计学差异.结论 AAV/siRNA-TIMP-1和Lenti/siRNA-TIMP-1均可有效抑制大鼠肝脏TIMP-1基因表达,进而发挥抗肝纤维化作用.