The Protection Of Ciclosporin A On Myocardial Ischemia-reperiusion Injury In Rats

ObjectiveTo study the effect of ciclosporin A pretreatment on myocardial ischemia-reperfusion and the possible mechanism of action.Hemodynamic, Lactate dehydrogenase(LDH) activity,myocardial infarct size,purine metabolite, the activity of purine metabolic enzymes and mitochondrial Na+,K+-ATPase and Ca2+-ATPase, mitochondrial swelling were observed.MethodsMyocardial ischemia-reperfusion models of48rats hearts was established with Langendorff model.48hearts were randomly divided into control group, reperfused group and CsA group. Control group were perfused with K-B solution for90min. Reperfused group were subjected to ischemia and reperfusion after30min perfusion with K-B solution. CsA group were also subjected to ischemia and reperfusion after30min perfusion, but we added CsA0.1mmol/L into the perfusate during the later20min perfusion.8rats in each group were randomly selected to measure heart rate (HR)、aortic flow (AF)、coronary flow (CF) and cardiac output (CO) of the three groups at10min、20min and30min respectively,then the LDH activity and the myocardial infarct size were measure.The purine releases in the coronary artery effluent after the whole process were measured by HPLC. The others8were used to isolate mitochondria with differential centrifugation to measure their purine metabolic enzymes, Na+, K+-ATPase and Ca2+-ATPase activity and mitochondrial swelling.Result1At10min and20min, there is no statistically significant difference between three groups. At30min, compared to control group and reperfused group (P<0.05), the coronary flow (CF) of CsA group slightly increased.2The LDH activity and the myocardial infarct size of CsA group were reduced by26.3%and31.3.1%respectively(P<0.05)compared to reperfused group3In reperfused group, the mitochondrial Na+, K+-ATPase and Ca2+-ATPase activities decreased(P<0.05)compared to other groups,but there were no significant differences between the control group and CsA group.4In CsA group, the extent of mitochondrial swelling were increased in comparison with control group but decreased in comparison with reperfused group.5Compared to the ischemia-reperfusion group,the activity of5’-NT, ADA, and XO in CsA group was significantly increased (P<0.05), and the activity of PNP in CsA group was significantly reduced (P<0.05).Conclusions1CsA pretreatment can slightly change the hemodynamic of rat hearts. When the hearts were pretreated by CsA (0.1mmol/), the CF increased compared to contral group, the increased CF can benefit heart blood-supply, thus protects ischemia-reperfused myocardium.2CsA pretreatment can reduce the myocardial infarct size and the LDH release of myocardial cells. Consequently. CsA pretreatment can protect I/R myocardium.3CsA pretreatment can protect the activity of mitochondrial Na+, K+-ATPase and Ca2+-ATPase and decrease the extent of mitochondrial swelling.thus attenuate the ischemia-reperfusion injury.4Ischemia-reperfusion injury can induce accumulation of various kinds of purine metabolin.Increase of purine metabolite indicates the acceleration of purine nucleotide degradation and decrease of ATP re-syntheses. CsA pretreatment reduced the content of purine metabolite, indicating CsA is capable of promoting the recovery of purine metabolism. Compared with reperfusion group, CsA group shows a higher activity of enzyme. The activity of5’-NT, ADA, and XO in CsA group was significantly increased (P<0.05), and the activity of PNP was significantly reduced as compared with the ischemia-reperfusion group. This alteration is beneficial to salvage synthesis pathway of purine, and has a myocardium protective effect.