绞股蓝叶水提物对糖尿病大鼠降血糖作用研究

Study on anti-hyperglycemia effect of aqueous extract from Gynostemma pentaphyllum leaves on diabetes rats

目的探讨绞股蓝Gynostemmapentaphyllum叶水提物对链脲佐菌素(STZ)诱导的糖尿病大鼠的降血糖作用及其机制。方法采用ip STZ的方法制备糖尿病大鼠模型,将21只造模成功的SD雄性大鼠随机分为模型组和绞股蓝叶水提物低、高剂量(100、500 mg/kg)组,另取7只正常大鼠作为对照组,分别于给药2周末和3周末禁食取血,检测血浆葡萄糖(空腹血糖)、三酰甘油(TG)的浓度,实时荧光定量PCR(q RT-PCR)检测骨骼肌肿瘤坏死因子α(TNF-α)和葡萄糖转运蛋白4(GLUT4)m RNA的表达,Western blotting检测骨骼肌GLUT-4总蛋白表达,免疫荧光染色观察GLUT-4蛋白在骨骼肌肌膜上的表达分布情况。结果与对照组比较,模型组大鼠的饮食、饮水量明显增加,而体质量以及骨骼肌的质量明显下降;血浆TG和空腹血糖以及骨骼肌中TNF-αmRNA的表达明显升高,而骨骼肌GLUT-4 mRNA、GLUT-4总蛋白及骨骼肌肌膜上GLUT-4蛋白的表达明显降低;与模型组比较,高剂量的绞股蓝叶水提物明显降低了STZ诱导的糖尿病大鼠的空腹血糖,逆转了骨骼肌TNF-αmRNA和肌膜GLUT-4蛋白的表达。结论绞股蓝叶水提物能够降低STZ诱导的糖尿病大鼠的血糖,其作用机制可能与增加骨骼肌肌膜GLUT-4蛋白表达和抑制骨骼肌炎症有关。

Objective The aim of this study was to investigate the anti-hyperglycemia effect and mechanism of aqueous extract from Gynostemma pentaphyllum(GP) leaves on STZ-induced diabetic rats. Methods Diabetic rat models were established by intraperitoneal injection of streptozotocin(STZ, 50 mg/kg). A total of 21 successful SD male rats were randomly divided into model group(STZ). G. pentaphyllum leaves aqueous extract low dose group(GP·H2 O-L, 100 mg/kg) and high dose group(GP·H2 O-H, 500 mg/kg), another seven normal rats were taken as the control group. Blood samples were taken from the 2 nd and 3 rd weekends to detect plasma glucose and triglyceride concentrations;Real-time PCR was used to detect the expression of TNF-α and GLUT-4 mRNA in skeletal muscle;Western blotting was used to detect GLUT-4 total protein in skeletal muscle;The expression of GLUT-4 protein on skeletal muscle sarcolemma was observed by immunofluorescence staining. Results The results showed that the food intake and water intake of the STZ group were significantly increased compared with the control group, while the body weight and skeletal muscle weight were obviously decreased;Plasma triglyceride and blood glucose concentrations and the expression of TNF-α m RNA in skeletal muscle were significantly increased, while the expression of GLUT-4 mRNA, GLUT-4 total protein and GLUT-4 protein in skeletal muscle sarcolemma was obviously decreased. Compared with the STZ group, the high-dose aqueous extract of G. pentaphyllum leaves significantly reduced the blood glucose of STZ-induced diabetic rats, and reversed the expression of TNF-α m RNA and GLUT-4 protein in skeletal muscle. Conclusion The aqueous extract from G. pentaphyllum leaves could reduce hyperglycemia in STZ-induced diabetic rats, and its mechanism may be related to increasing the expression of GLUT-4 protein on skeletal muscle sarcolemma and inhibiting skeletal muscle inflammation.