辛伐他汀抑制大鼠胰岛β细胞胰岛素分泌的机制研究

目的 观察辛伐他汀对大鼠胰岛β细胞葡萄糖刺激的胰岛素分泌(GSIS)的抑制作用及其机制.方法 8周龄健康雄性Wistar大鼠60只,体重250～300 g,饲养1周内分批处死.采用胆管注射胶原酶法提取大鼠胰岛,将新鲜分离或经24 h培养的大鼠胰岛按体积大小分为对照组(胰岛数=60)和辛伐他汀组(胰岛数=60),对照组给予Kreb-Ringer碳酸氢盐缓冲液,辛伐他汀组以100μmol/L辛伐他汀水浴30 min或过夜培养24 h.两组经2.8、5.5、11.1、16.7、25.0 mmol/L葡萄糖刺激后,采用37 ℃水浴法观测胰岛β细胞GSIS变化,选用生物化学发光法测定腺苷三磷酸(ATP)含量.两组间数据比较采用t检验.结果 100 μmol/L辛伐他汀水浴30 min后,在25.0 mmol/L葡萄糖刺激下,胰岛β细胞ATP含量较相应对照组明显下降(9.2±1.6)vs(12.1±1.9)pmol/胰岛,t=2.97,P＜0.05],GSIS较相应对照组明显减少(2.31±0.38 vs 3.19±0.41,t=3.154,P＜0.05).100μmol/L辛伐他汀过夜培养24 h后,在11.1 mmol/L葡萄糖刺激下,胰岛β细胞ATP含量较相应对照组明显降低(9.2±1.4)vs(11.9±2.0)pmol/胰岛,t=2.514,P＜0.05];在2.8 mmol/L葡萄糖刺激下,胰岛素分泌即已明显受到抑制(0.28±0.03 vs 0.47±0.05,t=2.460,P＜0.05).辛伐他汀浓度超过30 μmol/L时,可剂量依赖性地抑制GSIS(2.49±0.21 vs 3.17±0.23,t=2.445,P＜0.05).结论 高浓度辛伐他汀可能通过抑制胰岛β细胞ATP生成而抑制GSIS.

Inhibitory effect of simvastatin on insulin secretion from pancreatic islet beta-cells in rats

Objective To evaluate the inhibitory effect of simvastatin on glucose-stimulated insulin secretion (GSIS) and its mechanisms from pancreatic islet beta-cells in rats. Methods Eight-week-old male Wistar rats weighing 250 to 300 g were fed in a specific pathogen-free laboratory and killed within 1 week to isolate pancreatic islets. According to the average volume, freshly isolated or 24-hour cultured pancreatic islets were divided into the control group(incubated with Kreb-Ringer bicarbonate buffer, n =60)and the simvastatin group(incubated with 100 μmol/L simvastatin, n = 60). Stimulated by 2. 8, 5.5,11.1, 16. 7 and 25.0 mmol/L glucose respectively, the effect of 100 μmol/L simvastatin on ATP content and GSIS was compared in the two groups. GSIS was performed by the 37 ℃ batch incubation method and ATP content was measured by chemiluminescence method. t test was used for data analysis. Results Incubated with 100 μmol/L simvastatin for 30 minutes, in the presence of 25 mmol/L glucose, the ATP content was significantly reduced in comparison with the control group ((9. 2 ± 1.6) vs (12. 1 ± 1.9) pmol/islet, t =2.97, P ＜0.05), and the GSIS was significantly inhibited (2.31 ±0.38 vs 3. 19 ±0.41, t =3. 154, P ＜ 0. 05). Cultured with 100 μmol/L simvastatin for 24 hours, when the glucose was higher than 11. 1 mmol/L, simvastatin exerted a significant inhibition on ATP content compared with the control group ((9. 2 ± 1.4) vs (11.9 ±2. 0) pmol/islet, t =2. 514, P ＜0. 05). The inhibition on GSIS was found even in 2. 8 mmol/L glucose (0. 28 ± 0. 03 vs 0. 47 ± 0. 05, t = 2. 460, P ＜ 0. 05). When ＞ 30 μmol/L,simvastatin showed a dose-dependent suppression in GSIS (2. 49± 0. 21 vs 3. 17 ± 0. 23, t = 2. 445, P ＜0. 05). Conclusion At a higher concentration, simvastatin may inhibit GSIS by decreasing ATP content in pancreatic islet beta-cells.