金糖宁对MSG肥胖小鼠糖代谢及胰岛β细胞功能紊乱的影响

Effects of Jintangning on glucose metabolism and islets β cell function in monosodium glutamate( MSG) induced obese mice with insulin resistance

目的研究金糖宁(JTN)对谷氨酸钠(MSG)诱导的肥胖性胰岛素抵抗小鼠糖代谢及胰岛β细胞功能的影响。方法 MSG小鼠分别饲以含JTN(8,16 g·kg-1)的高蔗糖(蔗糖-普通饲料=1∶1)饲料作为低、高剂量组,连续给药近15周。实验期间,监测JTN对空腹血糖、糖耐量异常及胰岛素抵抗的影响;用高血糖钳夹技术评价JTN对MSG小鼠β细胞功能的影响;观察胰岛病理形态的变化;检测胰腺中与胰岛素合成、胰岛素信号通路相关因子mRNA水平的变化。结果长期给予JTN可显著改善MSG小鼠的糖耐量异常状态,增加胰岛素敏感性;降低空腹血糖,改善高胰岛素血症,增加MSG小鼠高血糖钳夹的GIR值和最大胰岛素分泌能力。结论金糖宁可显著改善肥胖性胰岛素抵抗MSG小鼠的糖代谢紊乱状态,改善胰岛β细胞功能。

Objective To evaluate the effects of the alpha - glucosidase inhibitor Jintangning （JTN） on glucose metabolism and beta cell function in monosodium glutamate （MSG） induced obese mice with impaired glucose tolerance （IGT） and insulin resistance. Methods MSG obese mice with insulin resistance were divided into four groups. The effects of JTN mixed with the chow （8 and 16 g·kg-1 50% sucrose chow） and Acarbose mixed with the chow （300 mg·kg-1 50% sucrose chow） on glucose metabolism were evaluated for about 15 weeks. In all groups, fasting plasma glucose, glucose tolerance tests and insulin tolerance tests were determined after 8 weeks treatment. Beta cell function was assessed by hyperglycemic clamp technique. The morphological alterations in pancreas were evaluated and the gene expressions in pancreas were deter- mined by real - time PCR. Results After chronic administration, JTN improved glucose intolerance and insulin sensitivity in MSG obese mice. In addition, JTN markedly decreased fasting blood insulin level and increased the maximum insulin secretion during the hyperglycemic clamp. It showed that JTN could improve beta cell function of MSG obese mice. Up - regulated gene expressions of PDX - 1, IRS2 and GLUT2 were found in pancreas after JTN treatment. Conclusion These results indicated that chronic administration of JTN regulate glucose metabolism and improved beta cell function in MSG obese mice.