Effects of sevoflurane preconditioning on myocardial connexin 43 during myocardial ischemia-reperfusion in rats / 中华麻醉学杂志

ABSTRACT

ObjectiveTo investigate the effects of sevoflurane preconditioning on myocardial connexin 43 (Cx43) during myocardial ischemia-reperfusion (I/R) in rats.MethodsMale adult Wistar rats weighing 220-250 g were anesthetized with intraperitoneal pentobarbital 40 mg/kg and heparin 500 IU/kg.Their hearts were excised and perfused in a Langendorff apparatus with K-H solution saturated with 95％ O2-5％ CO2 at 37 ℃ for 30 min.Sixteen isolated rat hearts were randomly assigned into 2 groups ( n =8 each)I/R group and sevoflurane preconditioning group (group SP).At 30 min of equilibration,group I/R received perfusion for another 20 min,the hearts were purfused with K-H solution saturated with 2.4％ sevoflurane for 15 min followed by 5 min washout with K-H solution in group SP.Then all the hearts underwent 40 min of ischemia followed by 60 min of reperfusion.HR,left ventricular developed pressure (LVDP),+ dp/dtmax and - dp/dtmax were recorded at the end of equilibration,immediately before ischemia and at 30 and 60 min of reperfusion.Myocardial tissues were obtained from apex for microscopic examination and from left ventricle for observation of distribution of Cx43 and determination of Cx43 expression.ResultsCompared with the baseline value at the end of equilibration, + dp/dtmax and - dp/dtmax immediately before ischemia and HR,LVDP,+ dp/dtmax and - dp/dtmax at 30 and 60 min of reperfusion were significantlydecreased in groups I/R and SP (P ＜ 0.01 ).Compared with that immediately before ischemia,HR,LVDP, + dp/dtmax and - dp/dtmax were significantly decreased at 30 and 60 min of reperfusion in groups I/R and SP (P ＜ 0.05 or 0.01).Compared with group I/R,HR,LVDP,+ dp/dtmax and - dp/dtmax were significantly decreased immediately before ischemia,HR,LVDP, + dp/dtmax and - dp/dtmax were significantly increased at 30 and 60 min of reperfusion ( P ＜ 0.01 ),and pathological injury was attenuated in group I/R.Myocardial Cx43 was unevenly distributed in group I/R,while evenly distributed in group SP.There was no significant difference in Cx43 expression between the two groups.ConclusionThe mechanism by which sevoflurane preconditioning protects myocardium against I/R injury may be related to redistribution of Cx43,but not Cx43 expression.