Protective effects of polarizing cardioplegia with Na(+) channel inhibitor in ex vivo rat heart preservation]

OBJECTIVE: To investigate the protective effects of polarizing cardioplegia with Na(+) channel inhibitor tetrodotoxin (TTX) in ex vivo rat heart preservation. METHODS: Using a Langendorff preparation, Wistar rat hearts were arrested and preserved with St.Thomas (STH) solution (n=10) or with polarizing cardioplegia (TTX, n=10) for 7 h in hypothermic storage (10 degrees Celsius). All the hearts then underwent 30 min of reperfusion. Pre-ischemia and post-ischemia indexes of the rat hearts were determined, including the hemodynamic parameters, myocardial enzymology, ATP content and ultrastructural changes. RESULTS: The recovery of hemodynamic parameters of the hearts in TTX group were better than those in STH group (P<0.01). In comparison with STH group, the leakage of creatine kinase (CK) and lactate dehydrogenase (LDH) in TTX group was significantly lower (P<0.05) and ATP level maintained a relative high level with better protected myocardial ultrastructure. CONCLUSION: TTX polarizing cardioplegia provides more effective long-term hypothermic preservation of isolated rat hearts than STH.