Effect Of Tetramethylpyrazine Pre-conditioning On The Expression Of Heat Shock Protein72 In Myocardium During Open Heart Surgery With Cardiopulnonary Bypass

Objective To evaluate heat shock protein 72 (HSP72) mRNA expression in myocardium of non cyanotic patients of congenital heart disease during cardiopulmonary bypass (CPB) surgery for correction of congenital heart disease, to investigate if tetramethylpyrazine (TMP) pre-conditioning can modify the expression of HSP72 during CPB ,and if TMP pre-conditioning can attenuate CPB-induced myocardial ischemia reperfusion injury through a self-protective mechanism.Methods Twenty eight non-cyanotic pediatric patients of congenital heart disease were randomly divided into the control group(n=14) and the TMP group(n=14). TMP was given to the treated group by intravenous dripping 3 mg.kg^-1 after anesthesia induction and adding 1 mg.kg^-1 in oxygenator during CPB. The levels of HSP72 mRNA were measured in the cardiac tissue from right atrium of the patients immediately before and after aortic cross-cramping (ACC) during cardiopulmonary bypass by semi-quantitative RT-PCR. Peripheral levels of AST, LDH ,CK ,CK-MB were measured before the CPB and 30 min after opening aorta and 24 h after cardiosurgery as markers of heart damage. The myocardial ultra structure was also observed before the CPB and 30 min after opening aorta.Results 1 There were no significant differences between the two groups in sex ,age,weight, ACC time ,CPB time and cardioplegic solution.2 The levels of HSP72mRNA increased after ACC in the two groups(P<0.05), The levels of HSP72 mRNA also increased after ACC in the TMP group than that of the control groupfP<0.05).3 The levels of the markers of cardiac injury AST,LDH,CK,CK-MB were higher during CPB in the two groups(P <0.05).The concentrations of all the markers of cardiac injury in the TMP group were lower than that of the control groups <0.05).4 The scores of myocardial mitochondria were higher after CPB in the two groups (P<0.01) . The scores of myocardial mitochondria in the TMP group were lower than that ofthe control group after CPB (P <0.05).5 The TMP group had milder alterations in myocardial ultrastructure than that of the control group after CPB.Conclusion These results suggest that HSP72 gene expression increased in myocardium of non cyanotic patients of congenital heart disease during CPB ,TMP pre-conditioning can induce HSP72 gene expression after ACC ,and protect myocardial mitochondria from ischemia reperfusion injury,and attenuates CPB-induced myocardial ischemia reperfusion injury through a self-protective mechanism.