中文摘要：

采用不同浓度酒精处理PC12细胞,观察酒精诱导细胞凋亡作用及凋亡过程中中性神经鞘磷脂酶（neutral sphingomyelinase,N-S Mase）活性及mRNA表达量的改变.结果显示,当酒精浓度达50 mmol/L以上时,作用24 h后,去血清培养的PC12细胞表现出较强的细胞增殖抑制作用（P〈0.05）并呈浓度依赖性.Hoechst 33258荧光染色结果显示处理组凋亡细胞增多,表现染色质凝集、细胞核变小、核碎裂成碎片等典型细胞凋亡特征性变化.琼脂糖凝胶电泳显示酒精处理组有不同程度的DNA断裂,呈凋亡细胞典型的梯状DNA.RT-PCR结果显示,不同浓度酒精作用PC12细胞2 h后N-S Mase表达升高.荧光分光光度法检测N-SMase的活性,显示酒精作用PC12细胞2h后酶活性升高,与去血清对照组相比差异显著（P〈0.05）.上述结果表明,酒精可导致PC12细胞凋亡并伴有N-SMase mRNA表达量增高,酶活性增强,说明酒精诱导PC12细胞凋亡与鞘磷脂循环有关.

英文摘要：

In this study,the author established the ethanol-induced apoptotic model of pheochromocytoma（PC12） cells.Using the model,the author examined activity and mRNA expression changes of neutral sphingomyelinase（N-SMase）in PC12 cells.The inhibition effect of ethanol on PC12 cells proliferation was examined by MTT assay.The result indicates the inhibition effect of ethanol on cell proliferation significantly in a dose-dependent manner（P0.05）.The nuclei morphological changes were detected by using Hoechst 33258 staining and fluorescent microscopy.Addition of ethanol with different concentration to PC12 cells,resulted in a number of morphological changes that are characteristic of apoptosis,these included cell shrinkage,chromatin compaction and nuclear fragmentation.Agarose gel electrophoresis of the DNA isolated from ethanol treated cells maintained in the absence of serum yielded the classical DNA laddering pattern of 180 to 200 bp fragments suggestive of apoptosis.The reverse transcriptase-polymerase chain reaction（RT-PCR） was used to detect the mRNA expression changes of N-SMase.A significant increase in mRNA expression and activity of N-SMase was observed in PC12 cells incubated for 2 hours in the presence of different concerntration ethanol（P0.05）.These results indicate that PC12 apoptosis induced by ethanol was correlated with the sphingomyelin cycle pathway.