中文摘要：

目的观察乙醇对小鼠胰岛瘤细胞（NIT-1细胞）凋亡的影响及Bcl-2、Bax和Caspase-3表达的变化，探讨乙醇诱发小鼠胰岛瘤细胞凋亡的分子机制。方法体外培养的小鼠NIT-1细胞，不同剂量乙醇（0、50、100、200、400mmoL／L）作用24h，单细胞凝胶电泳实验（SCGE），AnnexinV／PI双标记法流式细胞仪检测细胞凋亡情况。不同剂量的乙醇作用6、12、24h。RT-PCR法检测与凋亡有关的基因Bcl-2，Bax和Caspase-3 mRNA表达水平。结果SCGE实验结果显示，低剂量乙醇损伤不明显，高剂量（200、400mmoL／L）组DNA迁移率、DNA损伤程度分级、DNA平均迁移长度与对照组比较，差异均有显著性。AnnexinV／PI检测结果表明，200、400mmoL／L乙醇组NIT-1细胞凋亡率升高，与对照组相比，差异有非常显著性。乙醇作用6h，随着乙醇剂量增加，Bcl-2／BaxmRNA表达先升高后降低；乙醇作用12h，400mmoL／L剂量Bcl-2／Bax比值下降；作用24h，各剂量组Bcl-2／Bax比值均下降。Caspase-3mRNA表达水平与乙醇剂量和作用时间相关。400mmoL／L剂量组作用24h，Caspase-3mRNA表达增加。结论乙醇可诱发体外培养的NIT-1细胞凋亡，凋亡的发生很可能与Bcl-2家族和Caspase-3激活有关。

英文摘要：

Objective To investigate the effect of ethanol on apoptosis in mouse insulinoma cells（NIT-1 ceils） and to evaluate the pathway associated with the regulation of Bcl-2, Bax and Caspase-3.Methods After NIT-1 cells were treated with ethanol at concentrations of 0, 50, 100, 200 and 400 mmol/L for 24 h, single ceil gel electrophoresis （SCGE） and AnnexinV/PI methods were performed to detect the apoptosis. After NIT-1 cells were exposed to various concentrations of ethanol （same as above） for 6, 12 and 24 h, the levels of Bcl-2, Bax and Caspase-3 mRNA expression were determined by RT-PCR method. Results SCGE results showed that the low concentration of ethanol induced no obviously DNA damage in NIT-1 ceils, but the rate of DNA migration, degree of DNA damage and average length of DNA migration of 200 and 400 mmol/L ethanol-treated groups were significantly changed compared to those of untreated group. The results of Annexin V/PI assay indicated that the apoptosis rates of NIT-1 cells in 200 and 400 mmol/L ethanol- treated groups were higher than that of untreated group. At 6 h, the ration of Bcl-2/Bax mRNA expression was increased first, then decreased with the increasing of ethanol dosage. At 12 h and 24 h, the ration was decreased. By treatment at 400 mmol/L, the decrease was dramatically compared to control group. Ethanol increased the caspase-3 mRNA expression at high concentrations and long exposure time. At 24 h, the caspase-3 mRNA expression was increased significantly by treatment at 400 mmol/L. Conclusion Ethanol induced apoptosis in NIT-1 ceils and the potential molecular mechanism probably relates with the Bcl-2 family and Caspse-3.