急性高血糖影响小鼠第一时相胰岛素分泌的机制  

Impairment mechanisms of acute hyperglycemia in the first-phase insulin secretion in mouse

作　　者：赵一楠[1] 周迎生[1] 颜迪恩 高秀莹[1] 

机构地区：[1]首都医科大学附属北京安贞医院内分泌代谢科,北京100029

出　　处：《中国实验动物学报》2017年第5期479-485,共7页Acta Laboratorium Animalis Scientia Sinica

基　　金：国家自然科学基金资助项目(81641027);教育部留学回国基金资助项目(2012-940);北京市科委科研基金资助项目(Z131100004013044);北京市学科带头人基金资助项目(2013-2-006)

摘　　要：目的观察急性高血糖影响小鼠第一时相胰岛素分泌的功能及形态学变化特点。方法给C57/BL 6J小鼠完成颈静脉插管后输注20%高糖溶液4 h,建立急性糖毒性小鼠模型,行腹腔葡萄糖耐量实验(intraperitoneal glucose tolerance test,IPGTT)及口服葡萄糖耐量实验(oral glucose tolerance test,OGTT)评价葡萄糖耐量及胰岛素分泌功能。HE染色及电镜观察胰岛形态变化及细胞内胰岛素分泌颗粒亚细胞结构变化。结果 IPGTT实验中急性糖毒性组15 min血糖值较对照组显著增加[(10.3±0.33)mmol/L vs(19.3±1.66)mmol/L],上升87%(P<0.05),OGTT实验中30 min血糖值较对照组显著增加[(9.8±0.31)mmol/L vs(18.16±1.01)mmol/L],升高85%(P<0.05),且早期胰岛素分泌高峰受损且分泌延迟。GSIS实验中急性糖毒性组在基础状态时(葡萄糖浓度2.8 mmol/L)和高糖(16.7 mmol/L)刺激后,胰岛素分泌较对照组显著降低[(0.481±0.003)ng/m L vs(0.702±0.121)ng/m L,(2.43±0.03)ng/m L vs(4.07±0.34)ng/m L],分别下降46%和67%(P<0.05);胰岛素含量测定结果显示,急性糖毒性组比对照组降低[(97.01±2.05)ng/m L vs(65.12±0.42)ng/m L,(121.40±0.58)ng/m L vs(62.7±0.48)ng/m L],下降49%和94%(P<0.05)。HE染色显示急性糖毒性胰岛边界不规则、内部细胞排列不整;透射电镜可见细胞内胰岛素分泌颗粒空泡,线粒体嵴断裂。结论急性葡萄糖毒性使胰岛β细胞内胰岛素储备减少,导致第一时相分泌胰岛素峰值降低及延迟。Objective To clarify the impairment mechanisms of acute hyperglycemia in the first-phase insulin secretion in mice. Methods The mouse model of acute glucose toxicity was established by glucose infusion through jugular vein catheterization. The glucose and insulin levels were assessed by IPGTT and OGTT in the mice of acute hyperglycemia and control groups. The histology of pancreatic islets was observed using HE staining and the insulin granules and other cytoplasmic organelles were observed by electron microscopy. Results The mouse model of acute hyperglycemia was successfully established. The IPGTT showed that the blood glucose level was decreased by 87%（ 10. 3 ± 0. 33 mmol/L vs.19. 3 ± 1. 66 mmol/L） at 15 min in the acute hyperglycemia group compared with the control group. The OGTT showed that the blood glucose level was decreased by 85%（ 9. 8 ± 0. 31 mmol/L vs. 18. 16 ± 1. 01 mmol/L） at 30 min in the acute hyperglycemia group compared with the control group. However,the peak values of insulin secretion were delayed in both IPGTT and OGTT. Insulin levels at 2. 8 and 16. 7 mmol/L glucose stimulation in the acute hyperglycemia group was de-clined by 46% and 67% than the control group,respectively（ P〈0. 05）. Residual insulin content in islet β cells was declined by 49% at 2. 8 mmol/L and 94% at 16. 7 mmol/L glucose infusion than the control group（ P〈0. 05）. The histology showed irregular structure of pancreatic islets in the acute hyperglycemia group. The electron microscopy revealed that the amount of insulin granules was decreased,and more cytoplasmic vacuoles and swollen mitochondria were observed.Conclusions Acute intravenous glucose load decreases insulin content of islet β cells,leading to decrease and delay of the first-phase insulin secretion.

关 键 词：胰岛 急性高血糖试验 糖耐量试验 胰岛素分泌 组织学 超微结构 小鼠 

分 类 号：Q95-33[生物学—动物学]