应用RNA干扰治疗小鼠急性乙型肝炎病毒感染

RNA interference inhibits replication and expression of hepatitis B virus in mice

目的建立小鼠急性乙型肝炎病毒感染的动物模型,在此基础上观察小干扰RNA(siRNA)对HBV复制和表达的影响。方法通过尾静脉注射1.3倍的HBV真核表达质粒pHBV1.3建立小鼠急性乙型肝炎感染模型,再将其与针对乙型肝炎病毒核心区的siRNA表达载体(pSI C)共注射,于注射后第6天取血测血清HBsAg(ELISA),做肝组织HBcAg免疫组化,通过RT PCR检测肝组织HBVC区mRNA转录子的水平。同时设立PBS对照组、无关干扰组与突变干扰组。结果转染后第6天血清HBSAg在pHBV1.3感染组中高表达(A值为4.08～9.04,平均值为5.07±1.07,A值≥2.1为阳性),肝内HBcAg阳性率为5%～10%;pSI C干扰组HBSAg,HBcAg的表达均受到抑制,血清HBsAg阴性,A值为0.04～1.5,平均值为0.62±0.59,与感染组相比有显著性差异(P<0.01),肝内HBcAg几乎无表达,RT PCR示肝内HBVCmRNA水平明显降低。而无关干扰pGFP及突变的干扰序列pSI Cmut则无此作用。结论RNAi技术能特异,高效地抑制小鼠体内HBV的复制和表达,提示siRNA作为一种新型抗病毒药物的巨大潜能,而通过水动力法建立的小鼠急性乙型肝炎病毒感染的动物模型,一定程度上解决了长期以来缺乏合适的HBV感染动物模型的问题,为今后进行药物筛选及抗病毒治疗的研究拓展了新的思路。

Objective To develop a mouse model of acute hepatitis B virus infection and to observe the RNA interference-mediated inhibition of HBV replication and expression in ~the mouse model. Methods Thirty Balb/c mice were randomly divided into 5 equal groups: group A to be injected with pHBV1.3, naked plasmid containing 1.3 time HBV ayw type whole genome eukaryotic expression vector, via the caudal vein as infection group; group B to be injected with pHBV1.3 and pSI-C, plasmid expressing HBV-C specific short hairpin RNA, as interference group; group C to be injected with pHBV1.3 and pSI-C mut, a mutant RNAi vector, as mutant interference group; group D to be injected with pHBV1.3 and pGFP , siRNA transcription vector targeting green fluorescence protein (GFP); and group E to be injected with PBS as blank controls. Six days after blood was collected and the mice were killed and their livers were taken out. ELISA was used to measure the concentration of HBsAg in the serum. Immunohistochenmistry and RT-PCR were used to detect the expression of HBcAg and HBV C mRNA in the liver. Results Three days after injection the HBsAg expression in the sera of the infection group was strongly positive. Six days after injection expression of HBsAg was negative in the interference group and blank control group, and was positive in the infection group, mutant interference group, and irrelevant group, however, with significantly lower OD values in the latter 2 groups compared with in the infection group (both P<0.05). Six days after injection immunohistochemistry showed that HBcAg expression in liver was positive in the infection group, weakly positive in the mutant interference group and irrelevant interference group, and was negative in the blank control group and interference group. RT-PCR showed clear expression of HBV C mRNA in the infection group, mutant interference group, and irrelevant interference. Conclusion RNAi technique specifically and effectively inhibits the replication and expression of HBV. siRNA has significant potential to become a new type antiviral drug. The establishment of an animal model of acute HBV infection in mice by hydrodynamic injection of naked plasmid has solved, to a certain degree, the problem of lack of appropriate animal model of HBV infection.