甲基丙烯酸环氧丙酯体外诱导的人胚肺成纤维细胞DNA链断裂

甲基丙烯酸环氧丙酯（GMA）导致人胚肺成纤维细胞（HELFs）恶性转化及其潜在致癌机理尚未阐明. 本研究用0.5-5.0 mg·L^-1的GMA给体外培养的HELFs染毒2 h和12 h，或用5.0 mg·L^-1的GMA染毒15 min-24 h, 应用单细胞凝胶电泳技术（彗星试验）对GMA引起的HELFs DNA断裂作用进行了初步探讨. 琼脂糖凝胶电泳及流式细胞仪检测等方法观察了GMA对细胞凋亡的诱导作用. 结果表明, GMA可导致染毒细胞DNA发生剂量和时间依赖性链断裂. 用5.0 mg·L^-1的GMA染毒后仅1 h断裂作用即已显著, 并随染毒时间延长而递增, 至24 h时损伤最为严重. 但在同样条件下未观察到GMA对细胞凋亡的诱导作用. 结果提示GMA导致的非凋亡性DNA链断裂可能是其诱导HELFs恶性转化早期重要的遗传事件之一.

DNA strand break induced by glycidyl methacrylate in human embryonic lung fibroblasts in vitro

The mechanisms of cell transformation and potential carcinogenesis caused by glycidyl methacrylate (GMA) in human embryonic lung fibroblasts (HELFs) are not well understood. In this study, HELFs were exposed to 0.5-5. 0 mg·L^-1 GMA in vitro for 2 h and 12 h or to 5.0 mg·L^-1 GMA for 15 min-24 h and the induction of DNA strand break was studied using the single cell gel electrophoresis technique (comet assay). Meanwhile, the induction of apoptosis in exposed HELFs was investigated by agarose gel electrophoresis and flow-cytometry assays. The results showed that GMA could cause DNA strand break in exposed cells in a dose- and time-dependent manner. The significant break was found as early as 1 h after exposure and it was increased with time up to 24 h. The inducing effect of GMA on apoptotic response in HELFs, however, was not observed in the same conditions. These results strongly suggest that the induction of non-apoptotic DNA strand break be one of the important genetic events arisen at the early stage in the process of GMA-induced cell transformation.