运动性心肌肥大大鼠背根神经节降钙素基因相关肽基因表达的变化

Expression of Calcitonin Gene Related Peptide mRNA in Dorsal Root Ganglia of Rats with Exercise-Induced Cardiac Hypertrophy

目的:探讨运动性心肌肥大大鼠背根神经节降钙素基因相关肽基因表达的变化。方法:雄性SD大鼠随机分为对照组(n=33)和耐力训练组(n=33)。耐力训练组进行10周的跑台耐力训练,建立运动性心肌肥大模型。建模后48h,从两组随机抽取17只大鼠,连续3天进行力竭运动,最后一次力竭运动后即刻处死全部实验动物。记录力竭运动距离和大鼠体重,取大鼠心脏和腰段背根神经节,记录心脏湿重,采用荧光定量聚合酶链式反应技术测定大鼠背根神经节降钙素基因相关肽mRNA的表达量。结果:10周后,耐力训练组大鼠心脏重量与体重之比和力竭运动距离显著高于对照组(P<0.01)。与对照组比较,力竭运动前耐力训练组背根神经节CGRPmRNA表达显著下降(P<0.01),力竭运动后耐力训练组背根神经节CGRPmRNA表达与力竭运动前相比无明显变化,而对照组较力竭运动前显著下降(P<0.01)。结论:运动性心肌肥大大鼠背根神经节CGRP基因表达下调,力竭运动后表达保持稳定。

Objective The goal of this study was to explore the alteration of calcitonin gene related peptide mRNA in dorsal root ganglia of rats with exercise-induced cardiac hypertrophy. Methods Male SD rats were randomly divided into control group （n=33） and treadmill training group （n=33）. Training group underwent 10-week treadmill running to induce cardiac hypertrophy. 48 hours after the last training, 17 animals from each group were subiected to consecutive 3-day running on treadmill until exhaustion and the distance and body weight were recorded and all animals were killed immediately. The hearts were removed and wet weight recorded. Dorsal root ganglia were taken out and the expression of calcitonin gene related peptide mRNA in dorsal root ganglia was detected by real- time fluorescence quantitative polymerase chain reaction. Results As compared with the control group, the ratio of heart weight to body weight and distance of run to exhaustion increased significantly （P〈0.01） and expression of calcitonin gene related peptide mRNA in dorsal root ganglia decreased remarkably （P〈0.01） in treadmill training group. After exhaustive exercise, expression of calcitonin gene related peptide mRNA in control group decreased markedly （P〈0.01）, while treadmill training group remained unchanged. Conclusion The findings suggested that expression of calcitonin gene related peptide mRNA in dorsal root ganglia is down-regulated, but still kept at the physiological level after exhaustive exercise in rats with exercise- induced cardiac hypertrophy.