Investigation for the effect of donor endothelium bcl-xL gene transfection on transplant immunoreaction in rat aorta transplantation

Abstract

Objective To investigate the influence of bcl-xL overexpression in donor endothelia on recipient immunoreaction after rat aorta transplantation. Methods Enhanced green fluorescent protein (EGFP)-marked lentivirus express vector with Tie2 promoter of anti-apoptotic gene bcl-xL was constructed and transfected into donor SD rat by tail vein injection. The isogeneic and allogeneic aorta transplantation was performed between SD and SD rats as well as SD and Wistar rats. After one week of transplantation, the overexpression of bcl-xL gene in transplant aorta was detected by fluorescence microscope and real-time quantitative polymerase chain reaction (Real-time PCR). The serum from recipients was collected and transplant aortic endothelial cells, spleen cells as well as cytotoxic T lymphocytes (CTL) from donor and recipient were separated and cultured. The mixed lymphocyte reaction, CTL activity and complement-dependent antibody-mediated cytotoxicity were then performed to assess the influence of bcl-xL overexpression in donor endothelia on recipient immunoreaction after rat aorta transplantation. Results Bcl-xL gene was significantly overexpressed (8.5±1.1 vs. 1.0±0.2, t=17.050, P=0.002) in transplant aorta after transfection of lentivirus express vector with Tie2 promoter. The proliferation rate of recipient spleen cells stimulated by allogeneic donor spleen cells was significantly increased in contrast to stimulated by isogeneic donor spleen cells (14.2±1.8 vs. 1.0±0.1, t=23.599, P=0.001; 14.7±2.2 vs. 0.8±0.1, t=25.037, P=0.001). The survival rate of transplant aortic endothelial cells incubated by allogeneic recipient CTL and serum was significantly reduced in contrast to incubated by isogeneic recipient CTL and serum (14.5% vs. 92.7%, χ2=244.558, P=0.000; 8.9% vs. 95.8%, χ2=290.494, P=0.000; 15.1% vs. 96.7%, χ2=269.251, P=0.000; 10.1% vs. 94.7%, χ2=286.190, P=0.000). However, there were no significant differences of the proliferation rate (1.0±0.1 vs. 0.8±0.1, t=2.108, P=0.068; 14.2±1.8 vs. 14.7±2.2, t=-1.012, P=0.341) and survival rate (92.7% vs. 96.7%, χ2=3.078, P=0.079; 95.8% vs. 94.7%, χ2=0.497, P=0.481; 14.5% vs. 8.9%, χ2=2.917, P=0.088; 15.1% vs. 10.1%, χ2=2.286, P=0.131; and 96.6% vs. 97.3%, χ2=0.344, P=0.558; 91.5% vs. 92.1%, χ2=0.033, P=0.856; 19.8% vs. 15.4%, χ2=0.387, P=0.239; 10.2% vs. 13.8%, χ2=1.515, P=0.218) between transfected groups and nontransfected groups in both isogeneic and allogeneic transplantation. Conclusion No significant effect of bcl-xL overexpression in donor endothelia on recipient immunoreaction after rat aorta transplantation. Key words: Bcl-xL; Aorta; Transplantation; Immune