Role of mitochondrial permeability transition pore in attenuation of myocardial ischemia-reperfusion injury by sufentanil postconditioning in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of mitochondrial permeability transition pore (mPTP) in attenuation of myocardial ischemia-reperfusion (I/R) injury by sufentanil postconditioning in rats.Methods Sixty male Sprague-Dawley rats,aged 14-15 weeks,weighing 350-420 g,were randomly divided into 4 groups (n =15 each)sham operation group (group S),group I/R,cyclosporin A group (group CP) and sufentanil postconditioning group (group SP).Myocardial I/R was produced by occlusion of left anterior descending branch of coronary artcry for 30 min followed by reperfusion.In groups CP and SP,cyclosporin A 5 mg/kg and sufentanil 1 μg/kg were injected via the jugular vein at 5 min before reperfusion respectively,while the equal volume of normal saline was injected in group I/R.At 10 min of reperfusion,hearts were excised,the myocardial mitochondria were immediately isolated and the activity of mPTP was measured by spectrophotometry.MAP and HR were recorded at 30 min of equilibration,at 30 min of ischemia and at 120 min of reperfusion and rate-pressure product (RPP) was calculated.Arterial blood samples were obtained at 120 min of reperfusion for determination of the plasma cardiac troponin Ⅰ (cTnⅠ) concentration.The animals were then sacrificed for determination of infarct size (IS) and area at risk (AAR),and IS/AAR was calculated.The mitochondrial ultra-structure was examined with electron microscope.Results Compared with group S,the mPTP activity and plasma cTnI concentration were significantly increased,and MAP and RPP were significantly decreased in the other three groups (P ＜ 0.05).Compared with group I/R,the mPTP activity,plasma cTnI concentration and IS/ARR were significantly decreased in groups CP and SP,and MAP was significantly increased in group CP (P ＜ 0.05).Compared with group CP,MAP was significantly decreased (P ＜ 0.05),while no significant change was found in the other indexes in group SP (P ＞0.05).Significant mitochondrial swelling,and disruption and disappearance of cristae were showed in I/R group.The mitochondrial structure was more complete in CP and SP groups than that in group I/R,and the disrupted cristae were found in a small number of mitochondria in CP and SP groups.Conclusion The mechanism by which sufentanil postconditioning reduces myocardial I/R injury is related to inhibition of mPTP opening in rats.