The Pharmaeological Preconditioning Of Triiodothyronine On Myocardial Protection

Objective: To study the effect and its manchanism of Triiodothyronine(T3) pretreatment on isolated rat hearts after ischaemia/reperfusion.Methods: Fourty isolated hearts of SD rat were divided randomly into five groups (n=8). Control group; ischemia/reperfusion group; ischemic preconditioning group; T3 pretreated group; Gliberclamide(Glib)+T3 pretreated group , isolated rat heart were perfused by modified KH buffer in the model of langendorff. To detected the effect of cardiac function after ischemia/reperfusion and the activity of superoxide dismutast(SOD), the concentration of malondialdehyde(MDA). Lactate dehyodrogenase (LDH) creatine kinase (CK-MB); Myocardial ultrastructural changes were observed after reperfusion.Results: Compared with I/R group, T3(3.0ng/L) pretreated the isolated rat heart obviously increased coronary effluent, improved the heart function promoted activity of superoxide dismutase (SOD) ,reduced the malondialdehyde (MDA) content and reduced the content of LDH and CK-MB from coronary effluent. These protective effects were attenuated by 30μmol/l gliberclamide administered . Conclusions: Pretreatment with T3 have obviously protective effect to ischemia of rat heart which the protective effect could be related with the kATP channel. The protective effects of T3 pretreatment to ischemia/reperfasion ofmyocardial maybe connect with adenosine .