左卡尼汀对心肌肥厚大鼠TGF-β/Smads信号通路和心肌能量代谢的影响  

Effect of L-carnitine on TGF-β/Smads signal pathway and myocardial energy metabolism in rats with myocardial hypertrophy

作　　者：赵丹丹[1] 李伟红[2] 刘迪[3] 

机构地区：[1]辽宁医学院研究生学院,辽宁锦州121000 [2]辽宁医学院生理教研室,辽宁锦州121000 [3]辽宁医学院基础学院,辽宁锦州121000

出　　处：《解放军医学院学报》2016年第4期395-398,共4页Academic Journal of Chinese PLA Medical School

基　　金：辽宁省大学生创新创业训练计划项目(30720140107k;17115000524)~~

摘　　要：目的观察左卡尼汀(L-carnitine)对心肌肥厚大鼠TGF-β/Smads信号通路以及心肌能量代谢的影响,并探讨相关机制。方法 SD大鼠40只,随机分为4组:空白对照组、模型组、左卡尼汀低剂量组(50 mg/kg)、左卡尼汀高剂量组(100mg/kg)。模型组和左卡尼汀组采用异丙肾上腺素[5 mg/(kg·d)]连续注射10 d,制成心肌肥厚模型。左卡尼汀组于造模后第2天开始连续给药8周。测定全心质量指数(heart mass index,HMI)和左心室质量指数(left ventricular mass index,LVMI);HE染色,光镜下观察心肌细胞形态;测定大鼠心肌组织中游离脂肪酸(free fatty acids,FFA)、乳酸(lactate acids,LAC)、ATP含量;Western blot技术检测TGF-β1、Smad3蛋白表达。结果与空白对照组相比,模型组和左卡尼汀低、高剂量组HMI和LVMI均有明显升高(P<0.05);心肌细胞肥大,结构紊乱;心肌组织中FFA、LAC含量均明显升高,ATP含量明显降低(P<0.05);TGF-β1、Smad3蛋白表达水平均有明显升高(P<0.05)。与模型组相比,左卡尼汀低、高剂量组上述指标(除ATP含量)均明显降低,ATP含量明显升高(P<0.05),高剂量组更为显著。结论左卡尼汀对心肌肥厚的能量代谢有改善作用,亦可降低TGF-β1、Smad3蛋白表达水平,从而抑制TGF-β/Smads信号通路,保护心肌。Objective To observe the effect of L-carnitine on TGF-β/Smads signal pathway and myocardial energy metabolism in rats with myocardial hypertrophy and discuss its related mechanism. Methods Forty healthy SD rats were randomly divided into blank control group, model group, L-carnitine low dose group（50 mg/kg） and high dose group（100 mg/kg）. Myocardial hypertrophy model was established in model group and L-carnitine group with continuous injection of isoproterenol（Iso） for 5 mg/（kg·d） for 10 days. L-carnitine was injected in rats of L-carnitine group since the second day after modeling for eight weeks. Then the heart mass index（HMI） and left ventricular mass index（LVMI） were measured, myocardial cells were observed under light microscope by HE staining. The free fatty acids（FFA）, lactate acids（LAC） and adenosine triphosphate（ATP） contents in myocardial tissue of rats were detected, and the expression of TGF-β1 and Smad3 protein were detected by Western Blot. Results The HMI and LVMI of model group, L-carnitine low dose group and high dose group increased significantly when compared to blank control group（P 〈0.05）, myocardial cells were more hypertrophied and its structure became more disordered compared to blank control group. The content of FFA and LAC were higher than blank control group while ATP decreased（P 〈0.05）, and the expression of TGF-β1 and Smad3 protein increased significantly（P 〈0.05）. The content of ATP increased significantly while all other indexes decreased significantly in L-carnitine low dose group and high dose group when compared with model group（P 〈0.05）. Conclusion L-carnitine improves the energy metabolism of myocardial hypertrophy and restrains TGF-β/Smad3 signal pathway, thus it plays a protective role in the myocardial cells by reducing the expression of TGF-β1 and Smad3 protein.

关 键 词：心肌肥厚 左卡尼汀 心肌能量代谢 TGF-β/Smads信号通路 

分 类 号：R331.3[医药卫生—人体生理学]