锰诱导PC12细胞凋亡与P53、MDM2蛋白表达

Relationship between expressions of P53,MDM2 proteins and manganese induced apoptosis in PC12 cells

目的探讨锰对嗜铬细胞瘤细胞(PC12cells)凋亡的诱导作用及与抑癌基因P53、原癌基因MDM2蛋白表达的关系。方法以PC12细胞作为多巴胺能神经元的模型细胞,取对数生长期的PC12细胞,用含200,400,800μmol/LMnCl2的培养液分别染毒培养24,36,48h。四甲基偶氮噻唑蓝(MTT)法检测细胞的生长情况,流式细胞仪(FMC)和原位缺口末端标记法(TUNEL)检测细胞凋亡状况;用免疫细胞化学法检测细胞P53、MDM2蛋白表达强度。结果氯化锰可呈时间和剂量依赖性抑制PC12细胞的增殖和诱导细胞凋亡,抑制率为11.8%～73.6%,凋亡率为8.72%～53.60%。免疫化学法检测结果显示,随锰浓度的增高,P53蛋白的表达增加(P<0.01),而MDM2蛋白表达下降,差异有统计学意义(P<0.01),且呈剂量依赖关系。结论锰可诱导PC12细胞凋亡,上调P53基因的表达和下调MDM2基因的表达可能在其诱导PC12细胞凋亡中起着重要的作用。

Objective To study the relationship between apoptosis of PC12 cells induced by manganese and the levels of the expression of P53,MDM2 proteins.Methods PC12 cells in logarithm period were used as the model of dopaminergic neuron cells and incubated in culture media with 200,400,800 μmol/L manganese chloride（MnCl2） for 24,36,48 hours,respectively.MTT colorimetry test was performed to exam cell growth and livingness of PC12 cell exposed to various dose of manganese.Manganese induced apoptosis of PC12 cells was observed by flow cytometry（FCM）and terminal deoxynucleotidyl transferase-meidated dUTP nick end labeling（TUNEL）and immunohistochemistry was used to measure the expression of P53 and MDM2 proteins.Results Manganese suppress the proliferation of PC12 cells in dose and time-dependent manner and induce apoptosis of PC12 cells in dose-dependent manner.Manganese boosted the expression of P53 proteins and inhibited the expression of MDM2 protein in dose-dependent manner.Manganese induced apoptosis in PC12 cells was positively correlative to the expression of P53 and negatively correlative to the expression of MDM2.Conclusion Apoptosis of PC12 cells can be induced by manganese by enhancing the expression of P53 protein and prohibiting the expession of MDM2 protein.