多巴胺抑制PC12细胞增殖和诱导凋亡作用的研究

目的　研究多巴胺(DA)对PC12细胞的增殖抑制和诱导凋亡的作用，探讨帕金森病(PD)神经元的死亡机制。方法　应用免疫组织化学、流式细胞仪、电镜及电泳技术，研究DA对大鼠嗜铬细胞瘤PC12细胞的增殖抑制及诱导凋亡的作用。结果　适当浓度(0.5mmol/L)DA能显著抑制PC12细胞的生长并诱导其凋亡，在作用时间较短时(<12h)表现为对PC12细胞的生长抑制，此时流式细胞仪检测未见凋亡峰，但细胞周期显示S期细胞明显抑制。此时Bcl-2染色呈强阳性，电镜下细胞形态基本正常，可见线粒体、内质网肿胀及核分裂相减少。当作用时间延长时(>24h)，流式细胞仪可见典型亚二倍体凋亡峰，此时电泳可见典型DNA“阶梯状”电泳带，电镜可见核浓缩、染色体边聚等凋亡特征性核结构改变，Bcl-2染色阳性率降低。结论　DA具有抑制PC12细胞增殖和诱导凋亡作用，细胞凋亡参与了PD的病变过程。

The study of proliferationinhibition and apoptosis induced by dopamine on PC12 cell

Objective　 To study the effect of dopamine in inhibition of proliferation and induction of apoptosis in PC12 cell, and explore the mechanism of dopaminergic neuronal death in substantia nigra with Parkinson's disease (PD). Methods　Based on the immunohistochemical technology, the study of proliferation inhibition and apoptosis induced by dopamine in PC 12 cell was examined by flow cytometry, electron microscope and electrochromatography. Results　 Moderate concentration of dopamine could inhibit significantly the growth of PC 12 cells and induce apoptosis. DA could inhibit the proliferation within 12 hours and the typical apoptosis peak was not observed by flow cytometry, but exhibit a obvious inhibition on S phase of the cell cycle and the Bcl-2 expression could be found and the special alteration of mitochondria and endoplasmic reticulum could be found in electromicroscope. DA could induce apoptosis on PC12 cell beyond 24 hours, and the special apoptosis peak could be found by flow cytometry, the typical DNA“ladder” fragments by electrochromatography and specific ultrastructure changed in electromicroscope such as pyknosis could be found in the same time. Conclusions　Dopamine can inhibit proliferation and induce the apoptosis on PC 12. And apoptosis may be involved the pathogenesis of PD.