Objective To explore the chronic effects of excess glucose on INS-IE cells and isolated mouse islets. Methods Islets were isolated by the collagenase digestion from adult female NMRI mice (6-10 weeks) after induction of anesthesia by phenpbarbital. INS-IE cells and isolated mouse islets were cultured in RPMI 1640 supplemented with 11.1 or 25.0mmol/L glucose for 72h. respectively. Then the medium were changed to Krebs-Ringer buffer containing 3.3 or 16.7mmol/L glucose and incubated for 1 h. Correspondingly upper medium was collected for insulin assay. Total RNA was extracted from INS-IE cells after 72h incubation with different concentration of glucose, then cDNA was synthesized and mRNA expressions of Pdxl, insulin 1, insulin 2, and GLUT2 were determined by RT-PCR. Results After incubation with excess glucose, basal insulin secretion was increased in both INS-IE cells and isolated mouse islets (INS-IE cells: (10.47 ±0.78) vs (7.71 ±0.59) ng/10000 cells, P<0.01; isolated mouse islets: (3.85 ± 0.26) vs (2.18 ± 0.21) μg/L, p < 0.001], and glucose-stimulated insulin secretion was impaired [INS-IE cells: (17.11 ± 1.98) vs (30.76 ± 2.20) ng/10000 cells, P<0.001; isolated mouse islets: (14.78± 1.03) vs (20.46± 1.49)μg/L, P<0.01]. Pdxl, insulin 1, insulin 2, and GLUT2 mRNA levels were reduced in INS-IE cells after treatment of excess glucose. Conclusion Long-term exposure to supraphysiologic glucose concentrations may cause dysfunction of pancreatic islet cells.%目的 探讨高糖对胰岛β细胞INS-1E和小鼠胰岛的慢性作用.方法 雌性NMRI小鼠,6～10周龄,苯巴比妥腹腔注射麻醉,应用胶原酶技术消化胰腺分离胰岛.传代培养的INS-1E细胞和分离的小鼠胰岛分别于含11.1,25.0mmol/L葡萄糖的RPMI1640培养液中培养72h,然后于含3.3,16.7mmol/L葡萄糖的Krebs-Ringer缓冲液中培养60min,留取上清液行胰岛素测定.INS-1E细胞在含不同浓度的葡萄糖的RPMI 1640培养液中培养72h,提取其总RNA,合成相应的eDNA,再行RT-PCR检测胰十二指肠同源异形盒-1(Pdx1).胰岛素1(Ins1),胰岛素2(Ins2)和葡萄糖转运子2(Glut2)的基因表达.结果 高糖培养后INS-1E细胞和小鼠胰岛的基础INS分泌增加[INS-1E细胞:(10.47±0.78)vs(7.71±0.59) ng/10000细胞,P＜ 0.01;小鼠胰岛:(3.85±0.26)vs(2.18±0.21) μg/L,P＜ 0.001],糖刺激的INS分泌减少[INS-1E细胞:( 17.11±1.98) vs( 30.76±2.20) ng/10000细胞,P＜ 0.001;小鼠胰岛:(14.78±1.03)vs(20.46±1.49) μg/L,P＜0.01]:高糖处理后INS-1E细胞的Pdx1.Ins1,Ins2和Glut2的mRNA水平下降.结论 高糖对胰岛β细胞具有慢性毒性作用.
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