Effects of Different Intervention Occasion of Trimetazidine on Isoproterenol-induced Cardiac Hypertrophy in Rats

Objective To explore effects of different intervention occasion of Trimetazidine on isoproterenol-induced cardiac hypertrophy in rats.Methods Twenty-four rats were randomly divided into three groups:ISO group,TMZ1 group,and TMZ2 group.There were eight rats in each group.Rat cardiac hypertrophy models were established by subcutaneous injection of isoproterenol.In the experiment,the rats of ISO group were injected with Isoproterenol 20,10,5 mg/kg in the first 3 days;those of TMZ1 group were injected Isoproterenol with the same dose and time firstly,then,all the rats were intragastric administrated with trimetazidine 10 mg/(kg·d) from the 8th day of the experiment;TMZ2 group were intragastric administrated with trimetazidine 10 mg/(kg·d) for 7 days firstly,then were injected Isoproterenol with the same dose and time,at the same time,trimetazidine was given continually;another eight rats were set to the normal group(NS group),they were injected with physiological saline 3 mL for 7 days.After 4 weeks,the ratio of heart weight to body weight(HW/BW) and left ventricular weight to body weight(LVW/BW) were caculated.The pathological changes of myocardial tissue were observed and myocardial apoptotic index(AI) was detected by TUNEL.Results Compared with the ISO group,trimetazidine markedly reduced both myocardial necrosis and interstitial edema.HW/BW and LVW/BW in ISO group,TMZ1 group and TMZ2 group were statistically significant compared with NS group(all P0.05),those in TMZ1 group and TMZ2 group were statistically significant compared with ISO group(all P0.01),those in TMZ2 group were statistically significant compared with TMZ1 group(all P0.05).The AIs of ISO group,TMZ1 group and TMZ2 group were significantly higher than that in NS group(all P0.01),those of TMZ1 group and TMZ2 group were significantly lower than that of ISO group(all P0.01),that of TMZ2 group was significantly lower than that of TMZ1 group(P0.05).Conclusion Trimetazidine could significantly reduce the isoproterenol-induced myocardial necrosis,myocardial hypertrophy,reduce myocardial apoptosis,and trimetazidine could protect myocardium better after pretreatment.