牛磺酸对糖尿病大鼠膈肌的保护作用

Protective Effect of Taurine on Diaphragm in Diabetic Rats

【目的】探讨中药牛黄、全蝎的主要成分牛磺酸对大鼠膈肌的保护作用。【方法】SD大鼠24只,随机分为正常对照组、模型组和牛磺酸组;后2组大鼠均采用50mg/kg链脲菌素腹腔注射,复制糖尿病模型,牛磺酸组予以含10g/L牛磺酸的自来水,其他组予以自来水,自由饮用4周;制备离体大鼠膈肌条,测定其单收缩张力(pSC)、最大强直张力(pmax)、收缩时间(t收缩)、半舒张时间(t1／2舒张)、张力-频率曲线及疲劳指数(Ifatigue)的变化;检测血糖浓度以及膈肌组织中的超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量的变化,并观察各组膈肌组织超微结构的变化。【结果】模型组膈肌的 pSC、pmax、Ifatigue显著降低(P<0．01),t收缩、t1／2舒张明显延长(P<0．01),张力-频率曲线显示膈肌张力显著降低,膈肌组织中SOD活性显著降低(P<0．01),MDA含量增加(P<0．01),电镜下出现肌小节和线粒体形态改变;而牛磺酸组膈肌的 pSC、pmax、Ifatigue升高,t收缩、t1／2舒张缩短,膈肌张力和SOD活性增强,MDA含量下降(P<0．05或P<0.01),并可改善膈肌组织超微结构的改变。【结论】牛磺酸对糖尿病模型大鼠膈肌损伤的保护作用可能与其清除自由基,抗脂质过氧化,降低血糖的作用有关。

[ Objective] To observe protective effect of taurine, a main component of Calculus Boris and Scorpio, on diaphragm in diabetic rats. [ Methods] Twenty-four SD rats were equally randomized into normal control group, model group and taurine group. Except the normal control group, the other rats were given intraperitoneal injection of streptozotocin 50mg/kg to induce diabetic models. Taurine group was fed with 10g/L water solution of taurine, and the other two prepared. groups with water for 4 weeks. After treatment, the rats were executed and the isolated diaphragm strips were Single contraction （SC）, maximum titanic tension, contraction time, half relaxation time, force-frequency curve and fatigue index （FI） of the diap （SOD） and malondialdehyde （MDA） in hragm strips were examined. The contents of blood sugar, superoxide dismustase the diaphragm were detected and the diaphragm ultrastructure was also observed [Results ] SC, maximum titanic tension and fatigue index were decreased, contraction time and half relaxation time prolonged, diaphragm tension in force-frequency curve decreased, SOD activity reduced and MDA content increased in the model group （P 〈 0.01 compared with the normal control group）. Diaphragm fibers fractured, mitochondrion was swollen in diaphragm of the model group under electron microscope. Taurine could counteract the above changes in the model rats （P 〈 0.05 or P 〈 0.01 compared with the model group）. [ Conclusion] The protective mechanism of taurine on injured diaphragm of diabetic rats may be related to the clearance of free radicals, counteraction of lipid oxidation and the decrease of blood sugar.