益气健脾汤联合二甲双胍激活PI3K/Akt/mTOR通路调控自噬对抗糖尿病肌萎缩

Yiqi Jianpi Decoction Combined with Metformin Activate PI3K/Akt/mTOR Pathway to Regulate Autophagy and Resist Gastrocnemius Muscles in Type 2 Diabetic Muscular Atrophy

目的围绕糖尿病模型大鼠比目鱼肌磷脂酰肌醇三激酶(Phosphatidylinositol 4,5-bisphosphate 3-kinase,PI3K)/丝氨酸-苏氨酸激酶(Serine-threonine protein kinase,Akt)/哺乳动物雷帕霉素靶蛋白(Mammalian target of rapamycin,mTOR)信号通路、线粒体生物发生、泛素-蛋白酶体途径(Ubiquitinproteasome system,UPS)和自噬,研究益气健脾汤协同二甲双胍改善糖尿病肌萎缩的机制。方法随机选择6只雄性SPF级SD大鼠设为正常对照组(Control,C),其余大鼠采用高脂饮食诱导联合链脲佐菌素(Streptozotocin,STZ)法复制糖尿病大鼠模型,模型复制成功后,随机分为模型对照组(Saline,S)、二甲双胍干预组(Metformin,M)及益气健脾汤联合二甲双胍干预组(Y+M),每组6只。血糖仪检测大鼠空腹血糖(Fasting plasma glucose,FPG);大/小鼠抓力仪检测大鼠抓力;麦胚凝集素(Wheat germ agglutinin,WGA)染色及透射电镜法观察比目鱼肌肌纤维形态及线粒体超微结构;Western blot法检测线粒体生物发生,UPS-自噬及PI3K/Akt/mTOR通路蛋白表达。结果与M组比较,Y+M组大鼠FPG和体质量未见差异,但抓力上调、比目鱼肌湿重增高及线粒体自噬减少;进一步研究发现,Y+M组大鼠比目鱼肌线粒体生物发生和UPS相关蛋白未见差异,而自噬水平下调,同时PI3K/Akt/mTOR信号通路激活。结论益气健脾汤联合二甲双胍改善糖尿病性肌萎缩与激活PI3K/Akt/mTOR通路所介导的自噬抑制有关。

Objective To investigate the mechanism of Yiqi Jianpi Decoction combined with metformin in improving diabetic muscular atrophy,we focused on the phosphatidylinositol 4,5-bisphosphate 3-kinase(PI3K)/serine-threonine protein kinase(Akt)/mammalian target of rapamycin(mTOR)signaling pathway,mitochondrial biogenesis,ubiquitin-Proteasome system(UPS)and autophagy in musculi soleus of diabetic model rats.Methods Twenty-four SPF male SD rats were randomly divided into Control group(C),Model control group(S),Metformin treatment group(M)and Yiqi Jianpi Decoction combined with metformin treatment group(Y+M),6 rats in each group.The diabetic rat model was established by high fat diet combined with Streptozotocin(STZ)injection method.Fasting plasma glucose(FPG)and holding power were obtained by corresponding methods.The fiber morphology and mitochondrial ultrastructure of soleus muscle were observed by Wheat germ agglutinin(WGA)staining and transmission electron microscopy(TEM).Mitochondrial biogenesis,UPS-autophagy and PI3K/Akt/mTOR pathway protein expression were detected by Western blot.Results Compared with M group,there were no difference about FPG and body weight in Y+M group,while the holding power was up-regulated,weight of soleus muscle increased and mitochondrial autophagy decreased.Further studies showed that there were no difference in mitochondrial biogenesis and UPS related protein of soleus muscle in Y+M group,while autophagy level was down-regulated,and PI3K/Akt/mTOR signaling pathway was activated.Conclusion Yiqi Jianpi Decoction combined with metformin can improve diabetic muscular atrophy,which is related to the inhibition of autophagy mediated by PI3K/Akt/mTOR pathway.