Effects Of Heat And Exhausted Exercise On Rat's Hsp70 And Relevant Indexes

Purpose:to decide if heated exercise can cause myocardial injury and even damage exercise ability by studying the effects of acute exhausted exercise on HSP70 and relevant indexes level of rat' s myocardial muscle.Methods:48 male Sprague-Dawley rats was randomly and equally assigned to six groups as follows:control group(C),exercise group(E),one-hour heat exposure group(H),heated exercise group(HE),exercise and 24-hour recovery group(E' ),heated exercise and 24-hour recovery group(HE' ). Rats of E,HE,E' and HE' ran to exhaustion on a treadmill,while rats of H and H' was exposed in the heat for one hour.Rats of C,E,HE and H were killed immediately after exercise or heat exposure,and those of HE' and E' were killed after 24-hour recovery.Myocardial muscle and serum samples were collected for HSP,MDA,SOD,Na+-K+-ATPase,ANP and CK-MB level tests.Results:1.HSP level of E and E' significantly increased than that of C group(P<0.05 and P<0.01).Compared to HE' group,the HSP levels of E' and H' have significantly decreased(P<0.01).The HSP level of H group is significantly higher than that of C group.2.The SOD levels of H and HE have significantly decreased compared to that of C group(P<0.05 and P<0.01).And the MDA level of HE group is clearly higher than those of H and HE' group(P<0.05).3.The ANP and CK-MB levels of E group are significantly higher than those of C group,while the levels of HE group is higher than H(P<0.05) and those of E' and HE' group respectively lower than those of E and HE group. 1.Heat decrease the SOD level.Exercise increase the MDA level.High intensity exercise can inhibit the activity of Na+-K+-ATPase and can induce high level of CK-MB,which can lead to damage of exercise ability of rats.Heated exercise can induce lipid peroxidation and cause damage to normal cell membrane of myocardial muscle.2.High intensity exercise can induce the release of ANP in rat' s myocardial muscle,which improves the condition of myocardial ischemia. Heat and exercise can induce the expression of HSP70 in rat' s myocardial muscle and reach a peak after 24 hours,w hich can have protective effects on heat-induced myocardial muscle injury.3.After 24 hours recovery,the levels of HSP70,SOD,MDA,ANP,CK-MB and Na+-K+-ATPase all restores to normal.So the acute heated-exercise-induced myocardial injury may be temporary.