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中国应用生理学杂志 ›› 2021, Vol. 37 ›› Issue (6): 644-649.doi: 10.12047/j.cjap.6062.2021.084

• 研究论文 • 上一篇    下一篇

二甲双胍和西格列汀对胰岛素抵抗糖尿病前期KKAy小鼠胰岛β细胞功能的影响*

李萍1, 梁琳琅2△, 王宇2, 侯达2, 杨昕2, 杨博2   

  1. 1.北部战区总医院风湿免疫科,
    2.内分泌科, 辽宁 沈阳 110812
  • 收稿日期:2020-03-30 修回日期:2021-03-09 出版日期:2021-11-28 发布日期:2021-11-25
  • 通讯作者: Tel: 13309883533; E-mail: Lianglllj@sina.com
  • 基金资助:
    *辽宁省自然科学基金资助项目(201602776)

Effects of Metformin and Sitagliptin on islet cell function in insulin-resistant prediabetic KKay mice

LI Ping1, LIANG Lin-lang2△, WANG Yu2 , HOU Da2, YANG Xin2, YANG Bo2   

  1. 1. Department of Rheumatology, the General Hospital of Northern Theater Command, Shenyang 110812;
    2. Department of Endocrinology, Shenyang 110812, China
  • Received:2020-03-30 Revised:2021-03-09 Online:2021-11-28 Published:2021-11-25

摘要: 目的:探讨二甲双胍和西格列汀对胰岛素抵抗糖尿病前期KKAy小鼠胰岛β细胞功能的影响及其机制。方法:将30只6周龄KKAy小鼠随机分为普通饲料喂养组(C组,n=10)及高脂饲料喂养组(n=20),8周龄时将高脂饮食喂养的KKAy小鼠随机分为两组:二甲双胍干预组(Met组,n=10)和西格列汀干预组(SP组,n=10),持续灌胃8周。用口服糖耐量实验(OGTT)检测葡萄糖水平。检测空腹血清胰岛素及血浆脂质水平,计算胰岛素释放指数(HOMA-β)及胰岛素抵抗指数(HOMA-IR)。留取KKAy小鼠胰腺,连续切片分别胰岛素、胰高血糖素免疫荧光染色,ki67/INS双标记分析β细胞增殖情况、凋亡情况。Western blot方法测定胰腺转录因子PDX-1和MafA蛋白表达情况。结果:① OGTT结果提示,与C组比较,Met和SP组KKAy小鼠的空腹血糖、口服葡萄糖后30、60及120 min的血糖均显著降低(P均<0.01),血糖时间曲线下面积(AUC)显著降低(P<0.01,P<0.01)。与Met组比较,SP组口服葡萄糖后30及60 min的血糖无明显统计学差异,120 min的血糖显著降低(P<0.05),两组AUC无统计学差异。② 胰岛素耐量试验(ITT)结果提示,与C比较,Met和SP组KKAy小鼠的空腹血糖、注射胰岛素后30、60及90 min的血糖显著减低,ITT血糖曲线下面积(AUC)显著升高(P<0.01),而Met和SP组之间比较无明显统计学差异。③ C组胰岛中β细胞区域亮度较低,边缘散乱,给予二甲双胍后,β细胞区域及亮度有所增加;给予西格列汀治疗后,β细胞区域及亮度显著增加。C组胰岛中,α细胞在胰岛中分布无序,亮度较大。给予二甲双胍后,α细胞区域有所减少,亮度有所降低,一定程度向胰岛边缘的分布;给予西格列汀后,α细胞区域明显减少,亮度显著降低,在胰岛边缘分布。④ 与C组比较,Met组和SP组胰腺MafA表达水平明显升高,分别为1.63倍,1.58倍(P<0.01,P<0.01)。各组间胰腺PDX-1表达情况无显著差异。结论:对胰岛素抵抗糖尿病前期KKAy小鼠,给予二甲双胍可以维持胰岛的功能和形态,给与西格列汀可能促进β细胞增殖,提高胰岛素转录因子MafA的表达水平,防止糖尿病的发生发展。

关键词: 二甲双胍, 西格列汀, KKAy小鼠, 胰岛素抵抗, 胰岛β细胞, MafA, PDX-1

Abstract: Objective: To investigate the effects of metformin and sitagliptin on the function of islet β cells in insulin resistance pre-diabetic KKay mice. Methods: Thirty 6-week-old KKAy mice were randomly divided into two groups: normal diet fed group (NC group, n=10) and high-fat diet fed group (n=20). At 8 weeks, KKAy mice were randomly divided into two groups: metformin intervention group (met group, n=10) and sitagliptin intervention group (SP group, n=10), which were treated by gavage for 8 weeks. Glucose tolerance was measured by oral glucose tolerance test (OGTT), serum insulin level and plasma lipid level were measured by tail blood sampling, and HOMA-β and HOMA-IR were calculated. The mice were killed after blood collection, and the pancreas of KKAy mice was taken. The β cell volume of each group was compared by immunofluorescence staining of insulin and glucagon, respectively. The proliferation and apoptosis of β cell were analyzed by Ki67/INS. The expressions of pancreatic transcription factors PDX-1 and MafA were detected by Western blot. Results: ① The OGTT results indicated that blood glucose of KKAy mice at fast, 30, 60 and 120 min after oral administration of glucose in the Met and SP groups were decreased significantly compared with the NC group, and the area under the blood glucose time curve (AUC) was significantly reduced (P<0.01, P<0.01). There was no significant difference between the Met group and the SP group in blood glucose level at 30 and 60 min after oral administration of glucose. Compared with the SP group, the blood glucose of Met group at 120 min was decreased significantly (P<0.05). There was no significant difference in AUC between the two groups. ② The results of the insulin tolerance test (ITT) indicated that, compared with NC, the fasting blood glucose and the blood glucose at 30, 60 and 90 min after insulin injection in KKAy mice in the Met and SP groups were decreased significantly, and the area under the ITT blood glucose curve (AUC) was increased significantly (P<0.01), while there was no significant difference between the Met and SP groups. ③ In the NC group, the brightness of the areas of the islet β cells was low and the edges were scattered. After treated with metformin, the areas and brightness of the β cells were increased. After treatment with sitagliptin, the area and brightness of the β cells were increased significantly. In the NC group, the α cells were disordered in the islet distribution and the brightness was large. After the administration of metformin, the α cell area and the brightness were decreased, and distributed to the edge of the islet to a certain extent. After the administration of sitagliptin, there was a significant decrease in the area of the α cells, with a significant decrease in the brightness and distribution at the edge of the islet. ④ Compared with the NC group, the expression levels of pancreatic MafA in the Met group and SP group were increased significantly, which were 1.63 times and 1.58 times, respectively (P<0.01, P<0.01). There was no significant difference in the expression of pancreatic PDX-1 between the groups. Conclusion: In pre-diabetes mellitus KKAy mice with insulin resistance, metformin can maintain the function and morphology of pancreatic islets, and sitagliptin may promote the proliferation of islet βcells, improve the expression level of insulin transcription factor MafA, and prevent the occurrence and development of diabetes.

Key words: Metformin, sitagliptin, KKAy mice, insulin resistance, islet β cell, MafA, PDX-1

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