摘要目的 探讨颈交感干离断(TCST)对急性心肌梗死大鼠左室重构的影响.方法 健康清洁级成年雄性SD大鼠64只,体重230～250 g,随机分为4组(n=16):假手术组(S组)、心肌梗死组(MI组)、左TCST组(LT组)、右TCST组(RT组).采用结扎左冠状动脉前降支的方法 制备急性心肌梗死模型.S组只穿线不结扎左冠状动脉前降支,分离颈交感干,不离断;MI组制备心肌梗死模型,随后分离颈交感干,不离断;LT组和RT组在心肌梗死模型制备成功后,分别实施左、右侧TCST.于TCST后第4周,每组随机选取8只大鼠,称重,随后处死,取左心室组织,称量,计算左心室质量指数(左心室质量/体重),并采用体视学三维形态定量分析左室重构情况,测定左心室心肌细胞体积密度(V_v)、心肌组织总体积(V_t)和心肌细胞总体积(V_c),采用RT-PCR测定心肌c-fos mRNA的表达水平.结果 与S组比较,其余各组左心室质量指数增加,心肌c-fos mRNA表达上调,左心室V_t和V_c增大,MI组和LT组左心室V_v增大(P<0.01),RT组左心室V_v差异无统计学意义(P>0.05);与MI组比较,LT组左心室质量指数增加,心肌c-fos mRNA表达上调,左心室V_t和V_c增大(P<0.05或0.01),左心室V_v差异无统计学意义(P>0.05),RT组左心室质量指数降低,心肌c-fos mRNA表达下调,左心室V_v、V_t和V_c减小(P<0.05或0.01);与LT组比较,RT组左心室质量指数降低,c-fos mRNA表达下调,左心室V_v、V_t和V_c减小(P<0.05).结论 右侧TCST可下调心肌梗死大鼠心肌c-fos mRNA的表达,一定程度上抑制左室重构;而左侧TCST可进一步诱导c-fos mRNA表达,促进左室重构的发展.

abstractsObjective To investigate the effects of right or left transaction of cervical sympathetic trunk (TCST) on left ventricalar remodeling (LVRM) after acute myocardial infarction in rats and the mechanism. Methods Sixty-four adult mule pathogen-free SD rats (230-250 g) were randomly divided into 4 groups (n=16 each): group Ⅰsham operation (group S) ; group Ⅱ LVRM; group Ⅲ left TCST and group Ⅳ right TCST. Myocardial infarct was induced by ligation of left anterior descending branch (LAD) of coronary artery in group Ⅱ, Ⅲ and Ⅳ. Left and right TCST were performed immediately after myocardial infarct was successfully induced in group Ⅲ and Ⅳ respectively. In group S LAD and cervical sympathetic trunk were exposed but not ligated and transected. The animals were killed at 4 weeks after ligation of LAD and TCST. The weight of left ventricle was measured and left ventricle weight index calculated, Left veatricular myocardial tissue volume (V_t), the volume density of myocardial cells (V_v) and myocardial cell volmne (V_c) were quantitatively analyzed by stereological method. The c-fos mRNA expression in myocardium was determined by RT-PCR. Results The left ventricle weight index, V_t, V_c and c-fos mRNA expression were significantly increased in group LVRM (Ⅱ), left and right TCST (Ⅲ, Ⅳ) as compared with group S. Left ventricle weight index, V_v, V_t, V_c and c-fos mRNA expression were all significantly decreased in fight TCST group (Ⅳ), while left ventricle weight index, V_t, V_c and c-fos mRNA expression were significantly increased in left TCST group (Ⅲ) as compared with LVRM group (Ⅱ). Conclusion Right TCST down-regulates the increase in c-fos mRNA expression after acute myocardial infarction and inhibits the left ventricular remodeling while left TCST up-regulates the c-fos mRNA expression and promotes the development of left ventricular remodeling.