亚砷酸钠对NIT-1细胞胰岛素合成与分泌的影响

Effect of NaAsO_2 on insulin synthesis and secretion of NIT-1 insulinoma cells

目的观察亚砷酸钠(NaAsO2)对胰岛β细胞NIT-1胰岛素合成与分泌的影响。方法体外培养NIT-1细胞,NaAsO2处理后,以MTT法检测细胞的增殖活性,用ELISA测定胰岛素分泌情况,RT-PCR法检测胰岛素mRNA的表达。结果 (1)当NaAsO2浓度大于4μmol/L时抑制细胞增殖,细胞增殖抑制率随NaAsO2浓度的增加及作用时间的延长而增加。(2)作用24h,8μmol/L组不同浓度葡萄糖刺激的胰岛素分泌和胰岛素mRNA表达均明显减少(P<0.05);作用48h,4μmol/L组和8μmol/L组不同浓度葡萄糖刺激的胰岛素分泌和胰岛素mRNA表达均明显减少(P<0.05),而且8μmol/L组对高糖(16.5mmol/L)刺激的胰岛素分泌与基础(5.5mmol/L)胰岛素分泌差异无统计学意义。结论砷(As)对NIT-1细胞胰岛素分泌和胰岛素基因表达的影响与作用时间和剂量有关,胰岛素合成与分泌障碍可能是(As)影响胰岛β细胞功能进而引发糖尿病的机制之一。

Objective To investigate the effect of NaAsO2 on insulin synthesis and secretion of NIT-1 insulinoma cells（pancreatic islet β-cells）.Methods The NIT-1 cells were cultured in vitro,after treatment with NaAsO2,their proliferation activity was determined by MTT,glucose stimulated insulin secretion（GSIS） was measured by ELISA,and level of insulin mRNA expression was detected by RT-PCR.Results（1）The proliferation of NIT-1 insulinoma cells was inhibited in a time-and-dose dependant manner when the concentration of NaAsO2 was higher than 4 μmol/L.（2）In NIT-1 cells exposing to NaAsO2 for 24 h,the GSIS and Ins mRNA expression of NIT-1 insulinoma cells of the 8 μmol/L group were both significantly decreased（P〈0.05）.In exposing to NaAsO2 for 48 h,the GSIS and Ins mRNA expression of NIT-1 insulinoma cells of the 4 μmol/L and 8 μmol/L groups were both significantly decreased（P〈0.05）.And the GSIS of the 8 μmol/L group was not significantly different between the response to 16.5 mmol/L and 5.5 mmol/L glucose stimulation.Conclusion In a time-and-dose dependent manner,arsenic can exert inhibitory effect on insulin secretion and insulin mRNA expression of NIT-1 insulinoma cells.The disturbance of insulin synthesis and secretion may contribute to arsenic-impaired β-cell functions and to the development of DM.