益景汤对早期糖尿病大鼠脑微血管病变的影响及作用机制

Effects of Yi Jing Decoction on Cerebral Microangiopathy in Early Diabetes Mellitus Rats and Related Mechanism

目的基于TGF-β1/Smads信号通路,探讨益景汤对糖尿病(DM)大鼠脑微血管病变的影响及其作用机制。方法30只大鼠随机分为正常组、模型组和益景汤组,每组10只。正常组常规喂养,其余2组采用链脲佐菌素进行DM造模后,益景汤组取益景汤水煎液1.35 mL加蒸馏水稀释至3 mL,每天1次灌胃;模型组以生理盐水3 mL,每天1次灌胃。2组连续给药至16周。处死大鼠取各组完整脑实质进行称重并测量体积,采用光镜观察脑细胞及微血管形态;采用Western blot检测晚期糖基化终产物特异性受体(RAGE)、通路蛋白转化生长因子β1(TGF-β1)、同源物4重组蛋白(Smad4)以及通路下游血管相关结构蛋白纤维连接蛋白(fibronectin)、紧密连接蛋白5(claudin-5)、Ⅳ型胶原蛋白(collagenⅣ)的表达。结果①大鼠一般情况:益景汤组与正常组比较,大鼠体质量和脑实质重量减轻;与模型组比较,大脑体积增加(P均<0.05)。②HE切片形态:益景汤组与正常组比较,胶质细胞数量明显增加;与模型组比较,缺血神经元明显减少,未见神经纤维缠结,胶质细胞数量增多、体积增大,毛细血管增生不明显,血管壁薄,未见明显充血及出血区域。③Western blot检测:益景汤组与正常组比较,RAGE、TGF-β1、Smad4、fibronectin、collagenⅣ表达明显增加,claudin-5表达明显减少(P均<0.05);与模型组比较,RAGE、TGF-β1、Smad4、fibronectin、collagenⅣ表达降低,claudin-5表达增加(P均<0.05)。结论益景汤能够保护DM大鼠脑微血管结构,改善脑部血流灌注。

Objective: To investigate the effect of Yijing Decoction on cerebral microvascular lesions in diabetes mellitus(DM) rats and its mechanism based on TGF-β1/Smads signaling pathway. Methods: Thirty rats were randomly divided into normal group, model group and Yijing Decoction group, with 10 rats in each group. The normal group was routinely reared and the other two groups of rats were used to establish DM model with streptozotocin. After successful modeling, Yijing Decoction group was given Yijing Decoction by gavage, and the model group was given normal saline by gavage, once a day, continuous gavage for 16 weeks. After the experiment, the brain parenchyma was weighed and measured, and the morphology of brain cells and microvessels were observed under light microscope;western blotting was used to detect receptor for advanced glycation end products(RAGE), transforming growth factor-β1(TGF-β1), mothers against decapentaplegic homolog 4(Smad4), fibronectin, claudin-5 and collagen Ⅳ. Results: The body weight and brain parenchyma weight of rats in Yijing Decoction group were lower than those in normal group, and the brain volume was higher than that in model group. Compared with the normal group, the number of glial cells in Yijing Decoction group increased significantly;compared with the model group, the ischemic neurons in Yijing Decoction group were significantly reduced, while the number and volume of glial cells were increased;there was no nerve fiber tangle and no obvious area of hyperemia and bleeding in Yijing Decoction group;the capillary hyperplasia was not obvious, and the blood vessel wall was thin in Yijing Decoction group. Compared with the normal group, the protein expression of RAGE, TGF-β1, Smad4, fibronectin and collagen Ⅳ in Yijing Decoction group increased significantly, while the protein expression of claudin-5 decreased significantly;compared with the model group, the protein expression of RAGE, TGF-β1, Smad4, fibronectin and collagen Ⅳ in Yijing Decoction group decreased significantly, while the protein expression of claudin-5 increased significantly. Conclusion: Yijing decoction can protect cerebral microvascular structure and improve cerebral blood flow perfusion in DM rats.