重组CTLA4Ig腺病毒对巨噬细胞活性及移植后排斥反应的抑制作用

 目的研究重组CTLA4Ig腺病毒对巨噬细胞活性及移植后排斥反应的抑制作用及其初步机制。方法采用大鼠原位肝移植模型,供体移植前7d应用重组CTLA4Ig腺病毒,移植后动态观察移植物急性排斥反应病理学分级、巨噬细胞浸润程度、细胞凋亡程度、移植物局部及受体外周血IFN-γ水平。结果应用重组CTLA4Ig腺病毒后,CTLA4Ig可以在移植肝局部稳定表达,并在移植术后3,5,7,12d各时点排斥反应病理分级、移植物局部巨噬细胞浸润和肝细胞凋亡指数均较排斥对照组显著减低(P<0.01);巨噬细胞浸润与排斥反应分级呈显著相关(r=0.696,P<0.01)。对细胞因子IFN-γ的检测表明,应用重组CTLA4Ig腺病毒后,移植物局部IFN-γmRNA和蛋白水平明显受抑制,血清IFN-γ浓度在术后5,7,12d均较排斥时照组低(P<0.01)。结论应用重组CTLA4Ig腺病毒可以抑制IYN-γ表达,抑制巨噬细胞活性,从而减缓移植后急性排斥反应,抑制肝细胞凋亡,保护移植物功能。

Counteracting of recombinant Ad-CTLA4Ig on acute rejection following attenuation of macrophage infiltration in rat liver transplantation

OBJECTIVE To investigate the potential role of macrophages in acute rejection after orthotopic liver transplantation by inhibiting their infiltration on the basis of recombinant ad-CTLA4Ig therapy.METHODS Sparague-Dawly (SD) rat livers were oithotopically transplanted into Wistar rat recipients. Recombinant ad-CTLA4Ig was administered through the dorsal vein of penis 7 d before transplantation. Rejection grades, macrophage infiltration, cell apoptosis, IFN-γ levels in liver graft tissue specimens were observed at different time points. IFN-γ levels in the blood were detected using ELISA assay.RESULTS CTLA4Ig gene remained positive after liver transplantation. The rejection grades, macrophage infiltration and apoptotic index decreased obviously in CTLA4Ig-treated group on day 3,5,7 and 12 after liver transplantation (vs rejection group,P<0.01). There was a correlation between macrophage infiltration and rejection grades (r-0.696,P<0.01) .The down-regulation of IFN-γ mRNA and protein levels in liver graft tissue specimens was observed. Serum IFN-γ concentration was decreased obviously in CTLA4Ig-treated group on day 5, 7, 12 after liver transplantation (vs rejection group, P<0.01) .CONCLUSION Recombinant ad-CTLA4Ig can effectively prevent the expression of IFN-y and infiltration of macrophages, which lead to the protection of allo-grafts, due to the attenuation of acute rejection after rat liver transplantation, and the suppression of cell apoptosis.