高温环境下急性力竭运动对大鼠心肌HSP70及血浆心钠素的影响

Effects of Acute Exhausted Exercise on the Myocardial HSP70 and Plasma ANP of Rats in a High Temperature Environment

目的:探讨高温环境下急性力竭运动对大鼠心肌组织HSP70及血浆心钠素(ANP)的影响。方法:雄性SD大鼠48只,随机分为安静对照组(C)、运动后即刻组(E)、高温暴露1小时组(H)、高温运动后即刻组(HE)、运动后24小时恢复组(E’)和高温运动后24小时恢复组(HE’)6组,每组8只。E、HE、E’、HE’组均进行一次性力竭跑台运动。H组在周围环境温度33℃、相对湿度50%的环境中高温暴露1小时。C、E、HE、H组在力竭运动后即刻宰杀,HE’、E’组分别在高温及常温下运动后均在温度23℃、相对湿度50%的常温环境下恢复24小时后宰杀。测试大鼠心肌组织HSP70及血浆ANP、血清CK-MB水平。结果:(1)E组和E’组HSP70表达量较C组显著升高(P<0.05,P<0.01),HE’组显著高于H组及E’组(P<0.01)。H组显著高于C组(P<0.01)。(2)E组ANP和CK-MB水平显著高于C组(P<0.01),HE组显著高于H组(P<0.05);E’组和HE’组分别显著低于E组和HE组(P<0.01)。结论:(1)高温和运动均会诱导心肌HSP70高表达且24小时后表达最高,高温环境增强了力竭运动引起的HSP70的高表达,这可能会对高温及运动后造成的心肌损伤有一定的修复作用。(2)力竭运动即刻血浆心钠素升高,改善了心肌血液供应,同时也提示心肌有潜在受损的可能,但高温环境并未加强力竭运动所致的心钠素水平的增加。

Objective To investigate the effect of acute exhausted exercise in high temperature environment on the expression of myocardial HSP70 and plasma ANP level of in rats.Methods Forty eight male Sprague-Dawley rats was randomly and equally assigned to the following six groups：control group（C）,exercise group（E）,one-hour heat exposure group（H）,heat exposure and exercise group（HE）,exercise and 24 hours after exercise group（E’）,heat exposure and 24 hours after exercise（HE’）.Each group consisted of 8 rats.Rats in E,HE,E’and HE’ran on a treadmill until exhaustion,while rats in H and H＇ were exposed in a high temperature environment（33℃,50%RH） for one hour.Rats in C,E,HE and H were killed immediately after exercise or heat exposure.Rats in HE’and E’were killed 24 hours after exercise.Samples from myocardium and serum were collected for determining HSP70,ANP and CK-MB.Results（1）HSP70 levels in groups E and E’are significantly higher than that in group C（P〈 0.05 and P 〈0.01r,espectively）,and the level in group HE’is significantly higher than that in groups H and E’（P 〈0.01）;The HSP70 level in group H is significantly higher than that in group C.（2）The ANP and CK-MB levels in group E are significantly higher than that in group C,and in group HE is higher than in group H（P 〈0.05）;The HSP70 levels in group E’and HE’significantly decrease comparing to that in groups E and HE（P 〈0.01）.Conclusions（1）Both heat exposure and exercise can induce the increased expression of myocardial HSP70 in rats and the peak expression is seen 24 hours after exercise.The increased expression of HSP70 may have protective effects on the heat-induced myocardial injury.（2）The increased ANP levels in plasma immediately after exhausted exercise improves the blood circulation in myocardium and hints the potential possibility of myocardial damage.Howevert,he high temperature environment does not strengthen the increase of plasma ANP level that caused by exhaustive exercise.