EFFECTS OF CARDIOPLEGIA WITH TETRODOTOXIN ON INTRACELLULAR SODIUM OVERLOAD OF ISCHEMIA/REPERFUSION CARDIOMYOCYTES

Aim:To investigate the effects of polarizing cardioplegia solution with sodiumchannel inhibitor tetrodotoxin(TTX)on intracellular free Na~+ concentration([Na~+]_i)in isolated cardiomyocytes of rat.Methods:Ventricular myocytes with beating were isolated from adult rat hearts by enzymatic dissociation,randomly created in group base,group STH2(contrast group of ischemia/reperfusion)and group TTX(treated group).Both Group STH2 and group TTX were arrested by St.Thomas No.2 cardioplegia solution and TTX cardioplegia solution respectively, the arrest/re-beating cell model imitating MIRI being established,and imagcd by laser scanning confocal microscopy(LSCM)for measuring [Na~+]_i of cardiomyocytes in different period.The morphology of cardiomyocytes was observed under the inverted microscope.Results: [Na~+]_i of cardiomyocytes in both group TTX and group STH2 after re-beating was higher than that in group base(P0.01),and[Na~+]_i in group TTX was lower than that in group STH2(P0.01).During arrest,the elevation of[Na~+]_i in group TTX was lower than that in group STH2.During arrest,the elevation of[Na~+]_i in group TTX was lower than that in group STH2.Morphologically,after re-beating,the ratio of active cardiomyocytes with normal form in group TTX was higher than that in group STH2(P0.01).Conclusion:Contrast depolarized cardioplegia solution,TTX cardioplegia solution could alleviate ischemia reperfusion injury and intracel lular Na~+ overload of cardiomyocytes.