糖尿病大鼠胰岛脂质分解的变化及意义

The changes and significance of lipolysis in pancreatic islets of diabetes rats

目的观察糖尿病大鼠胰岛中甘油三酯(TG)、脂质分解和激素敏感性脂肪酶(HSL)的变化,探讨胰岛细胞内脂质分解在糖脂毒性中的作用。方法采用雄性Wistar大鼠,通过高脂饮食+小剂量链脲佐菌素建立糖尿病模型(DM组),同时设立正常对照组(NC组)和单纯高脂饮食组(HF组)。成模4周后,检测各组大鼠的血糖、血脂、胰岛素分泌、胰岛中TG含量及HSLmRNA和蛋白的表达;测定胰岛细胞游离脂肪酸的释放以代表脂质分解。结果与NC组相比,HF组大鼠血糖没有明显变化,但是胰岛素和血脂均明显升高(P<0.05或P<0.01);DM组大鼠血糖、血脂水平显著高于NC组(P<0.05或P<0.01),而胰岛素水平与NC组相似。HF组大鼠胰岛内TG含量较NC组有明显的增加(P<0.05),DM组胰岛内脂质积聚更严重,约为NC组的2.15倍。与NC组相比,HF组和DM组大鼠胰岛脂质分解和HSL表达明显增加(P<0.05或P<0.01)。结论精尿病状态下,胰岛细胞内脂解和HSL的表达明显增加,这既是维持细胞内脂质代谢平衡的重要因素,又体现了机体对脂毒性的保护。

Objective To explore the roles of lipolysis and hormone sensitive lipase （HSL）of pancreatic islets in glucolipotoxicity by observing the changes of triglyceride（TG）, lipolysis and HSL in the islets of diabetes rats. Methods Diabetes rats （DM） were induced by feeding the fat rich food and injecting the streptozotoein. Normal rats （NC） and rats fed with fat-rich food （HF） were provided. Blood glucose, plasma insulin, plasma lipids, TG and expression of HSL gene and protein in the islets were measured. The measured free fatty acid released from the islets represented the activity of lipolysis. Results The blood glucose showed no difference between HF group and NC group, but plasma insulin add plasma lipids in HF group rats were significantly elevated as compared with NC group（P〈0.05 or P〈 0.01 ）. The blood glucose and plasma lipids in DM group rats were significantly increased（P〈0.05 or P〈0.01）. The plasma insulin in DM group rats was similar to that in NC group. Compared with NC group, TG in the islets of rat in HF group was significantly increased（P〈0.05）, TG accumulation in the islets of diabetes rats was as 2. 15 times as that of NC group. At the same time, the lipolysis and the expression of HSL in HF and DM group markedly increased（P〈0.05 or P〈0.01）. Conclusions The increase of lipolysis and HSL activity in the islets of diabetes rats could be a compensation to alleviate the TG accumulation and to keep the metabolism balance of glucose and lipids, and may protect against fatty acid induced islet dysfunction.