胰岛素和CTLA4Ig共表达基因治疗小鼠糖尿病模型的效果

Efficiency of co-expression of CTLA4Ig and insulin genes in treating diabetes mellitus

为观察导入CTLA4Ig基因能否延长胰岛素基因治疗的疗效时间,静脉注射链脲佐菌素(streptozotocin,STZ)制备1型糖尿病(type 1diabetes mellitus,T1DM)小鼠模型,将24只造模成功的雄性C57小鼠随机分为注射空载腺病毒组、表达胰岛素的腺病毒组(recombinant adenovirus vector/insulin,rAdV/Ins)和共表达胰岛素和CTLA4Ig基因的重组腺病毒(recombinant adenovirus vector/insulin-CTLA4Ig,rAdV/Ins-CTLA4Ig)组,每组8只。采用实时定量聚合酶链反应(quantitative real-time polymerase chain reaction,qRT-PCR)方法检测胰岛素、CTLA4Ig及其相关基因在小鼠肝组织的mRNA表达水平。应用简便血糖仪定期检测小鼠血糖水平。rAdV/Ins-CTLA4Ig组小鼠肝组织中CTLA4Ig mRNA的表达量显著高于rAdV/Ins组和空载腺病毒组(P<0.01)。rAdV/Ins-CTLA4Ig组小鼠肝组织中IFN-γmRNA的表达显著低于空载腺病毒组(P=0.04)。与注射空载腺病毒组相比较,rAdV/Ins-CTLA4Ig和rAdV/Ins两组小鼠的血糖水平显著降低(均P<0.05),且rAdV/Ins-CTLA4Ig组小鼠较rAdV/Ins组小鼠能维持更长的正常血糖时间(P<0.01)。胰岛素和CTLA4Ig共表达基因的重组腺病毒能转染小鼠肝脏,CTLA4Ig能在肝内成功表达并通过抑制炎症反应延长了胰岛素基因表达时间。

The aim of this study was to explore whether co-expression of CTLA4Ig can extend the effect of insulin gene therapy. Animal model of type 1 diabetes mellitus（TiDM） was established by STZ injection in male C57 mice. Twenty four mice with TIDM were randomly divided into 3 groups（8 mice in each group） ：adenovirus vector group, rAdV/Ins group, and rAdV/ Ins-CTLA4Ig group. RT-PCR was used to detect mRNA expressions of CTLA4Ig, insulin and other related genes in the liver. Blood glucose was measured by glueometer. The results showed that the expression of CTLA41g mRNA was significantly in creased in the rAdV/Ins-CTLA4Ig group when compared with the adenovirus vector group（ P 〈0.01 ） and the rAdV/Ins group （P 〈0.01）. Compared with the adenovirus vector group, the relative expression of IFN-γ mRNA in the rAdV/Ins CTLA4Ig group was significantly reduced（P=0.04）. Level of blood glucose was reduced significantly in both rAdV/Ins-CTLA4Ig group and rAdV/Ins group, but the duration of maintaining normal blood glucose was much longer in the rAdV/Ins-CTLA4Ig group （P〈0.01 ）. We conclude that the adenovirus vector-mediated co-expression of CTLA4Ig and insulin gene can be transfected into the liver of mice, and co-expression of CTLA4 gene extends the effect of insulin gene therapy by inhibiting inflammation induced by the viral vector.