蚕丝水解物对实验性糖尿病大鼠血糖调节作用的机制研究

Mechanism of silk hydrates on modulating the blood glucose metabolism in rats with experimental diabetes

从胰岛素的受体和受体后作用机制来探讨蚕丝水解物 (silk hydrates,SH)调节糖代谢的机理。选用若干只雄性成年 Wistar大鼠随机分为 2组 :一组经尾静脉注射小剂量链脲佐菌素 (STZ,30 m g/kg BW) 3周后 ,加喂高糖、高脂、高热量饲料。选择具有 型糖尿病特征 ,即糖耐量异常、胰岛素高于或等于对照组的38只大鼠为糖尿病模型组。另一组 36只大鼠不注射 STZ,仅喂普通饲料 ,为对照组。再分别将 2组大鼠各随机分为 2小组 :糠尿病对照组、糖尿病 + SH组 ;正常对照组、正常 + SH组。每日给予 SH 1g/kg BW,观察 12周 ,在实验末每组随机取半数大鼠做骨骼肌胰岛素受体结合实验 ;其余大鼠做葡萄糖摄取实验。结果表明 :1SH能显著改善糖尿病大鼠的糖耐量 ,但对正常大鼠及糖尿病大鼠胰岛素的分泌基本没有影响 ;2给予 SH后 ,糖尿病大鼠骨骼肌细胞膜胰岛素受体对 1 2 5 I-胰岛素的特异结合率没有明显提高 ,仍低于正常大鼠 ;仅低亲和力位点上的受体亲和力常数显著增加 ;3给予 SH后 ,糖尿病大鼠的骨骼肌细胞对葡萄糖的摄取显著增加 ;其自由摄食状态下的肝糖原、骨骼肌糖原的含量显著增加 ;4给予 SH后 ,糖尿病大鼠部分血脂紊乱得以改善。结果提示 SH主要是通过胰岛素的受体后作用机制来改善

Thirty eight adult male Wistar rats injected with streptozotocin(STZ) 30mg/kgBW via tail vein and fed on a diet of high fat,high sucrose and high calorie for 3 weeks and then for another 8 weeks were successfully established as the diabetes model(type Ⅱ diabetes mellitus).The effects of feeding silk hydrates(SH)for 12 weeks on the activities of insulin receptors and postreceptors were observed.The results showed that:1)SH greatly improved the glucose tolerance of diabetic rats,but no effect on the secretion of insulin in rats with or without diabetes; 2)Only the low affinity constant of insulin binding rates(K2) in skeletal muscle cell membranes of diabetic rats fed with SH were obviously increased,the high affinity binding constant and the number of receptors were not changed; 3)the uptake of glucose in skeletal muscle of diabetic rats fed on SH was significantly increased.4)SH partly improved the metabolism of serum lipids. The results indicated that SH could modulate the metabolism of blood glucose mainly through the mechanism on the activity of insulin postreceptor.