Study Of Protective Effects Of Catechins On Hypoxia-Reoxygenation Injury In Cultured Neonatal Rat Cardiac Myocytes And Their Mechanisms

Objective To filter catechins which has obvious protective effects on hypoxia-reoxygenation injury in cultured cardiac myocytes and to study their protective effects, and then to discuss their mechanisms; in order to set up foundation of empoldering highly effective drug treating Myocardial Ischemia Reperfusion Injury( MIRI).Method The model of hypoxia-reoxygenation injury in cultured cardiac myocytes was set up by making the pure cultured neonatal rat cardiac myocytes be lack of oxygen for 3 hours and then afford oxygen 1 hour. 50% Effective Concentration(EC5o) of catechins protecting hypoxia-reoxygenation injury in cultured cardiac myocytes was obtained. Basing on the EC50, we filtered GCG, EGCG and ECG which have the obvious protective effects. We also studied their protective effects on hypoxia-reoxygenation injury in cardiac myocytes, the primary guide lines being observed are: livability, morphologic change and beating rates of cardiac myocytes, activity of LDH, SOD, GSH-Px , and MDA concentration in culture medium. The activity of ATPase in the cardiac myocytes membrane was also observed. Different protective effects of GCG and EGCG on different hypoxia-reoxygenation injury models were studied and analyzed. Those models were respectively made with normal cultured cardiac myocytes and the cultured cardiac myocytes whose Protein Kinase C had been interdicted or G protein had been lost activity. The changeof inducible enzyme was analyzed also. Through those ways, we try to discuss the mechanisms of catechins protecting hypoxia-reoxygenation injury in cultured cardiac myocytes.Result GCG, EGCG and ECG can obviously enhance the livability, activitiy of SOD and GSH-Px of hypoxia-reoxygenation injured cardiac myocytes. They can ameliorate morphologic change of injured cardiac myocytes and reduce their release of LDH and MDA. The protective effects of GCG and EGCG were weaken when the PKC of injured cultured cardiac myocytes had been interdicted or their G protein had been lost activity, although they had obvious protective effects on on hypoxia-reoxygenation injury in cultured neonatal rat cardiac myocytes. GCG and EGCG have the effects of increasing the volume of Na+ K+—ATPase and Ca2+ Mg2+— ATPase in membrane of hypoxia-reoxygenation injured cardiac myocytes.Conclusion GCG EGCG and ECG have the evident protective effects on hypoxia-reoxygenation injury in cultured neonatal rat cardiac myocytes. The mechanisms of protective effects of catechins on the cultured neonatal rat myocardial cells injured by hypoxia-reoxygenation are related to the antioxidation effects of catechins and its effects of restraining Ca2+ influxion, and the transmission of protein kinase C and G protein.