【摘要】 目的研究乙基亚硝基脲(N-ethyl-N-nitrosourea熏ENU)诱发原代大鼠脑星形神经胶质细胞DNA损伤及对P53、P21蛋白表达的影响。方法采用机械分离技术,在体外培养大鼠脑神经胶质细胞,通过传代培养的方法纯化大鼠脑星形胶质细胞。给予不同浓度ENU(1.7、3.4、6.8、13.6、27.2mmol/L)染毒,采用单细胞凝胶电泳(single-cellgelelectrophoresis,SCGE)和免疫组织化学的方法观察ENU对星形胶质细胞DNA的损伤作用和抑癌基因p53、p21的产物P53、P21蛋白在细胞中表达。结果不同染毒浓度下,各染毒组对星形胶质细胞均有不同程度DNA损伤作用,各染毒组拖尾细胞百分率与阴性对照组比较,差异均有统计学意义(P<0.01),且随受试物浓度增加而增加,表现出明显的剂量-效应关系(r=0.916)。各染毒组细胞DNA的迁移距离(尾长)与阴性对照组比较,差异均有统计学意义(P<0.01)。在13.6、27.2mmol/LENU染毒组,P53有阳性表达,与阴性对照组比较,有统计学意义(P<0.01),而P21在各实验组均未见阳性表达。结论ENU对大鼠脑星型胶质细胞的毒性主要表现在诱导细胞遗传物质DNA损伤以及抑癌基因p53的表达水平升高。更多还原

【Abstract】 Objective To determine whether N-ethyl-N-nitrosourea( ENU) can induce DNA damage and may have an adverse effect on the expression of P53 and P21 in the primary cultured astrocytes. Methods The astrocytes of postnatal SD rats were cultured and purified by physical isolation and by subculture, immunohistochemistry was employed in the test of the expression of P53 and P21 protein in astrocytes in vitro at different exposed concentrations of ENU(1.7, 3.4, 6.8, 13.6 and 27.2 mmol/L), single cell gel electrophoresis assay was used to test DNA damage. Results The result of single cell gel electrophoresis(SCGE) showed that obvious damage was found in each exposed group with a significant increased rate of tailed astrocytes and dose-dependent relationship compared with the control group. A significant expression of P53 protein was seen at 13.6 mmol/L and 27.2 mmol/L of ENU, no change was observed in the P21 at any exposure concentrations. Conclusion ENU exposure may cause the DNA damage and up regulate the expression of P53 protein in cultured astrocytes of rat, which also indicates that the astrocyte may be one of the target cells for ENU.更多还原