腺相关病毒介导的大鼠移植肝基因转移

Adeno-associated virus mediated gene transfer into liver graft in rat

目的 研究腺相关病毒载体介导的移植肝基因转移的可行性和转导率。方法 以绿色荧光蛋白 (GFP)作为报告基因 ,在大鼠供肝冷保存前经门静脉注入不同剂量 (1× 10 10 pfu/ml、5× 10 10pfu/ml和 1× 10 11pfu/ml)的带有绿色荧光蛋白的腺相关病毒载体 (AAV GFP) ,保存后行异体肝移植 ,术后 2、4及 8周取供肝组织活检 ,运用免疫荧光显微镜和流式细胞仪检测GFP的表达 ,计算转导率 ,观察不同剂量的AAV GFP及不同保存时间 (1h、4h和 10h)对转导率的影响。结果 3个剂量组肝移植术后第 4周移植肝细胞内均可观察到GFP的表达 ,随着AAV GFP剂量的增加 ,转导率也增加 (6 %、15 %和 34 % ) ;随着冷保存时间的延长 ,转导率逐步提高 (15 %、32 %和 5 4% ) ;除移植肝细胞外 ,脑、心、肺、肾、脾脏内均未见GFP的表达 ;与对照组比较 ,移植肝功能的差异无显著性。结论 在模拟临床肝移植条件下 ,利用腺相关病毒可将目的基因转移入移植肝细胞内 ,且能高效表达 ;转导率随病毒剂量的增加、冷保存时间的延长而提高 ;经冷保存途径腺相关病毒的转染具有嗜肝性 ;

Objective To investigate the feasibility of gene transfer into liver graft using adeno-associated virus (AAV) vector.Methods Rat liver grafts were harvested and preserved in 4℃ UW solution. The grafts were infected ex-vivo via portal vein perfusion with replication-defective AAV vectors encoding green fluorescence protein (GFP) diluted in UW solution. Liver grafts biopsies were performed 2 weeks, 4 weeks and 8 weeks after transplantation. Transduction rate was assessed by immune fluorescence microscopy and flow cytometry. The relationship between AAV quantity and transduction rate was observed: Three groups (n=8/group) of liver grafts perfused at a dose of 1×10 10 pfu/ml, 5×10 10 pfu/ml and 1×10 11 pfu/ml AAV via portal vein, were stored in UW solution at 4℃ for 1h, then transplanted. The correlation between cold preservation time and transduction rate was studied: Liver grafts (n=8/group) were perfused with AAV vectors suspended in UW solution at a dose of 5×10 10 pfu/ml, kept at 4℃ UW solution for 1, 4, and 10 h, then transplanted. Liver grafts were biopsied on postoperative 28 days.Results GFP expression was initially observed in all the experimental liver grafts at 4th week after transplantation. The transduction rate was elevated with the increase of AAV quantity ( 6%, 15%, 34% respectively ) and with prolonged cold preservation time (15%, 32%, 54% respectively). However, GFP was not observed in the brain, heart, lung, kidney and spleen of recipient rats. Conclusions AAV vector can be used for in situ delivery of foreign genes to liver graft under current clinical transplantation condition. The transduction rate was elevated with the increase of AAV quantity and prolonged cold preservation time. AAV transfection via cold preservation possessed organ-tropism for liver graft. Function of liver graft was not evidently influenced by gene transfer.