葡萄糖浓度波动对INS-1细胞胰岛素分泌的影响

目的初探葡萄糖浓度波动对大鼠胰岛素瘤INS-1细胞胰岛素分泌功能影响机制。方法将INS-1细胞随机分为正常糖组（5.5 mmol/L葡萄糖培养液培养）、持续高糖组（16.7 mmol/L葡萄糖培养液培养）、波动组（用16.7 mmol/L葡萄糖培养液培养2 h,再换5.5 mmol/L培养3 h,每天重复3次,夜间9 h维持在5.5 mmol/L的培养液中）、N-乙酰半胱氨酸（N-acetyl-L-cysteine,NAC）＋正常糖组、NAC＋持续高糖组、NAC＋波动组,后3组的培养基中均预先负载终浓度为1.0 mmol/L的NAC,余干预措施相同,均干预72 h。荧光素酶方法检测细胞内三磷酸腺苷（adenosine-triphosphate,ATP）含量,放射免疫分析法测定胰岛素分泌水平。结果 INS-1细胞ATP含量及胰岛素分泌水平在持续高糖组及波动组均较正常糖组显著下降,且波动组下降更明显,差异有高度统计学意义（P〈0.01）。NAC＋波动组及NAC＋持续高糖组细胞ATP含量及胰岛素分泌水平分别较波动组及持续高糖组显著增加,差异有统计学意义（P〈0.05）。结论持续性高糖及波动性高糖损伤INS-1细胞的胰岛素分泌可能与减少细胞ATP含量有关,且波动性高糖较前者更严重,氧化应激可能是波动性高糖及持续性高糖导致INS-1细胞ATP减少的机制。

Effect of fluctuating high glucose on insulin secretion in INS-1 cells

Objective To investigate the effects of fluctuating high glucose on insulin secretion in INS-1 cells.Methods The INS-1 cells(pancreatic β cell lines) were divided into the normal control group(NC group,exposed to the medium containing 5.5 mmol/L of glucose),sustained high glucose group(SHG group,exposed to 16.7 mmol/L of glucose) and fluctuating high glucose group(FHG group,exposed to 16.7 mmol/L of glucose 2 h,then 5.5 mmol/L of glucose 3 h,repeated three times one day,and kept in 5.5 mmol/L of glucose 9 hours during night time),NAC+NC group,NAC+SHG group and NAC+FHG group [they were all exposed to medium containing 1.0 mmol/L N-acetyl-L-cysteine(NAC),all cultivated for 72 h].The ATP levels of INS-1 were examined by the luciferinluciferase kit,and the insulin was detected by radioimmunoassay.Results The ATP and insulin secretion decreased significantly in SHG group and FHG group than that in NC group(P < 0.01).While addition of N-acetyl-L-cysteine to above two groups partially prevented decreasing in the ATP levels and insulin secretion(P < 0.05).Conclusion Reduction in the ATP levels in INS-1 cells may be related to the impairment of insulin secretion,and oxidative stress may play important role in it.