人AAT基因在糖尿病细胞治疗中对β细胞的免疫保护作用

目的:建立稳定表达人α1-抗胰蛋白酶(hAAT)基因的NIT-hAAT细胞系,观察hAAT基因在糖尿病细胞治疗中对β细胞的免疫保护作用。方法:构建hAAT的真核表达载体,转染并筛选得到NIT-hAAT细胞系。将该细胞系移植到糖尿病模型小鼠左肾包膜下,通过检测不同移植组小鼠的血糖、血清胰岛素水平和生存期,观察不同移植细胞对糖尿病的治疗效果;RFPCR检测移植部位的hAAT表达情况以及对小鼠左肾进行石蜡切片和苏木素-伊红(HE)染色,鉴定hAAT对NIT-1细胞的免疫保护作用。结果:糖尿病小鼠接受NIT-hAAT细胞移植后,hAAT可有效延长NIT-1细胞的存活时间,使血糖明显降低并维持至正常血糖水平,小鼠的生存率也明显提高(P<0.05);移植部位的病理HE染色结果证实hAAT可明显减轻小鼠对移植物炎症反应。但RT-PCR结果显示hAAT在体内的表达量随时间增长而出现逐渐下降,NIT-hAAT细胞最终因免疫排斥反应而失去功能。结论:NIT-hAAT细胞具有明显抑制体内免疫排斥反应,可有效延长β细胞存活时间,对胰岛细胞移植具有免疫保护作用。

The immunosuppressive and protective ability of hAAT for beta cells transplantation in diabetes

Objective:To investigate the protective effect of human α 1-antitrypsin(hAAT) in the cell transplantation of diabetes.We constructed NIT-hAAT cells,which can express human α1-antitrypsin(hAAT) gene stably.Methods:Transfect NIT-1 cells with the eukaryotic expression vector of hAAT.The positive clones were screened and called NIT-hAAT cells.These cells were transplanted into the subrenal capsule of diabetes model mice,and then detect the blood glucose,serum insulin level and survival time of mice from different transplantation groups,so that to observe the effect of distinct treatment in diabetes.Besides,in order to observed the immune protection of hAAT in vivo,the expression of hAAT in transplant parts were detected by RT-RCP and the biopsy of tissues were stained by hematoxylin and eosin(HE).Results:After NIT-hAAT cells transplantation,the blood glucose levels of mice declined effectively and maintained to be normal.The expression of hAAT can prolong the survival time of graft.Transplantation with NIT-hAAT cells could enhance the survival rate of diabetes mice(P<0.05).Besides,the result of pathology test with HE staining confirmed that the hAAT could significantly reduce graft inflammation.But the expression of hAAT was gradually decreased in vivo by the RT-PCR,which was indicated that the Nit-hAAT cells were loss their function eventually by immune rejection.Conclusion: NIT-hAAT cells expressing hAAT can inhibit the immune rejection and prolong the survival time of β cells.