[Effects of different oxygen flow rates on myocardial ischemia-reperfusion injury in rabbits].

ABSTRACT

OBJECTIVE: To explore the effects of different oxygen flow rates during cardiopulmonary bypass (CPB) on myocardial ischemia-reperfusion (IR) injury in rabbits. METHODS: Thirty rabbits were randomized equally into groups A, B and C to receive controlled oxygen reperfusion at low, normal and high flow rates (25, 50, and 80 ml.kg(-1).min(-1), respectively). Serum concentration of CK-MB and cTnT were tested by ELISA before the operation (T0) and after 30 min (T1), 2 h (T2), 12 h (T3) and 24 h (T4) of reperfusion. W/D, SOD and MDA of the myocardium were determined before and at 60 min after reperfusion. The ultrastructural alterations of the myocardium were observed. RESULTS: Serum concentration of CK-MB and cTnT in the 3 groups increased significantly after the operation, and their levels were the lowest in group A (P<0.05). W/D and MDA in the myocardium was also the lowest, while SOD the highest in group A (P<0.05). Ultrastructural pathologies were found in all the 3 groups, but relatively mild in group A. CONCLUSION: Low oxygen flow rate during controlled reperfusion may protect the myocardium from IR injury in rabbits.