单纯疱疹病毒胸腺激酶基因系统抑制体外培养的人眼球筋膜囊成纤维细胞增殖的研究

Anti-proliferative effect of herpes simplex virus thymidine kinase gene system on human Tenon capsule fibroblasts in vitro

目的研究单纯疱疹病毒胸腺激酶(HSV-tk)基因系统对人眼球筋膜囊成纤维细胞(HTFs)增殖的抑制作用及其作用机制。方法构建含HSV-tk基因的逆转录病毒载体pL(tk)SN并转入包装细胞系PT67进行病毒包装,G418筛选抗性克隆并扩大培养收集病毒上清,测定病毒滴度。透射电镜观察鉴定病毒颗粒;聚合酶链反应(PCR)技术鉴定tk基因在病毒基因组中的整合。用病毒感染HTFs细胞,G418筛选并扩大培养,逆转录聚合酶链反应(RT-PCR)技术和免疫印迹法检测tk基因的表达;加不同浓度前药更昔洛韦(GCV)后,以MTT法检测tk基因对HTFs细胞增殖的抑制作用;采用Hoechst33258染色及流式细胞仪检测凋亡细胞;电镜观察细胞形态学改变。结果酶切鉴定结果显示成功构建了逆转录病毒载体pL(tk)SN,电镜下包装细胞产生的病毒颗粒呈椭圆形,直径约100nm;病毒基因组中,PCR扩增出了tk基因;测得病毒滴度为4×107cfu/ml;被转染的HTFs细胞,用RT-PCR及免疫印迹法检测到tk基因在mRNA与蛋白水平均有表达;HSV-tk-GCV系统对HTFs细胞增殖的抑制作用表现为剂量依赖性,5×10-3g/L的GCV作用5d可将细胞全部杀死,IC50为6×10-4g/L,HSV-tk-GCV系统对HTFs细胞的杀伤机制表现为坏死与凋亡,凋亡率随GCV浓度的升高而增加。结论HSV-tk基因系统能有效抑制人眼球筋膜囊成纤维细胞的增殖,作用机制表现为细胞的坏死与凋亡。(中华眼科杂志,2006,42:212-217)

Objective To observe anti-proliferative effect of herpes simplex virus thymidine kinase gene system （HSV-tk） on human Tenon capsule fibroblasts （HTFs） and it＇s mechanism. Methods Retroviral vector was constructed containing HSV-tk gene and transfer to packaging cell line PT67. The positive clones was selected with G418 and the supernatant was collected which contains virus particles. The titer of the virus was also calculated. The virus particles were verified by transmission electron microscope （TEM）. PCR was carried out to detect the integrity of tk gene into viral DNA genome. HTFs cells were infected with the virus and the positive clones were selected for propagation culture. RT-PCR and Western blot were used to detect tk gene expression. The anti-proliferative effect of tk gene on HTFs cells was determined by MTY. Apoptosis of cells was detected by Hoechst 33258 DNA staining and flow cytometry. The morphologic changes of the cell were observed by TEM. Results The retroviral vector pL（tk） SN was constructed successfully which was verified by enzyme cutting. The shape of virus particles derived from the package cells appeared to be oval or spherical under TEM with the diameter around 100 nm. The tk gene was detected in the viral DNA genome by PCR. The virus titer was 4 ×10^7cfu/ml. The expression of tk gene was detected by RT-PCR and Western blot both in mRNA and protein level. The anti-proliferative effect of tk gene on HTFs cells was dose-dependent, all cells were died 5 days after 5 x 10-3 g/L GCV being added, IC50 =6 × 10^-4g/L. Both necrosis and apoptosis were observed in this study and the apoptesis rate was increased with increasing dose of GCV. Conclusions The proliferation of HTFs cells in vitro could be effectively inhibited by the killing effect of HSV-tk-GCV system through the pathway of necrosis and apoptosis.