摘要
目的观察二甲双胍(MF)对慢性高糖和高脂处理后的HIT-T15细胞(β细胞系)胰岛素受体(IRc)酪氨酸蛋白激酶(TPK)活性的影响,探讨MF对β细胞糖脂毒性,即β细胞胰岛素抵抗的改善作用机制。方法实验分为对照组、对照+MF组、高糖组、高糖+MF组、高脂组、高脂+MF组。将HIT-T15细胞分别接种于含有5.5mmol/L、16.7 mmol/L葡萄糖(G)及0.5 mmol/L软脂酸的培养液中,培养48 h后,加入2.5μg/mL MF干预24h。用放射性酶分析法测定β细胞IRc TPK活性。结果高糖〔(52.5±18.6)pmol/(min.μg)〕和高脂组〔(54.6±14.0)pmol/(min.μg)〕HIT-T15细胞IRc TPK活性分别较对照组〔(119.4±29.1)pmol/(min.μg)〕降低(P<0.01);予2.5μg/mL MF干预24 h后,高糖和高脂组IRc TPK活性较干预前增高〔(113.0±29.8)vs(52.5±18.6)pmol/(min.μg),P<0.01;(98.6±26.1)vs(54.6±14.0)pmol/(min.μg),P<0.01〕,且与对照组相比差异无统计学意义。MF对对照组HIT-T15细胞IRc TPK活性无明显影响。结论高糖和高脂可抑制β细胞IRcTPK活性。MF能明显改善受高糖及高脂所抑制的HIT-T15细胞IRc TPK活性,且恢复到接近正常水平。提示MF对糖脂毒性所致β细胞胰岛素抵抗的改善作用可能与增加IRc TPK活性有关。
Objective To study the effect of metformin on insulin receptor（IRc） protein tyrosine kinase（PTK） activity of HIT-T15 cell exposed to high glucose and free fatty acid（FFA） concentration,and to explore the mechanism of metformin（MF） improving β cell insulin resistance.Methods HIT-T15 cells were incubated for 48 h in a medium containing 5.5-16.7 mmol/L glucose and 0.5 mmol/L palmitic acid respectively.The cells were reincubated for another 24 h with or without 2.5 μg/mL MF.The PTK activities of IRc were measured by radioactive enzyme assay.Results The enzymatic activities of IRc PTK were significantly decreased to HIT-T15 cells having the exposure to high glucose or high FFA concentration,when compared to control（（52.5±18.6） or（54.6±14.0） vs（119.4±29.1） pmol/（min·μg）,P〈0.01 respectively）.The enzymatic activities of IRc PTK in HIT-T15 cells reincubated with 2.5 μg/mL MF for an additional 24 h were significantly increased vs MF free group（（113.0±29.8） vs（52.5±18.6） pmol/（min·μg）,·98.6±26.1） vs（54.6±14.0） pmol/（min·μg）,P〈0.01 respectively）,and were no significant difference in comparison with control group （P〉0.05）.Conclusion The enzymatic activities of IRc PTK are significantly decreased in HIT-T15 cells chronically exposed to elevated glucose or free fatty acids levels.Metformin can restore approximately normal enzymatic activities of PTK of HIT-T15 cells,of which the PTK activities have been impaired by chronic exposure to high glucose or free fatty acids levels.
出处
《四川大学学报（医学版）》
CAS
CSCD
北大核心
2007年第5期819-821,共3页
Journal of Sichuan University(Medical Sciences)
基金
国家自然科学基金(批准号30470827)资助
