舒芬太尼预处理对大鼠心肌缺血再灌注时PI3K/Akt的影响

Effect of sufentanil preconditioning on myocardial P-Akt expression in rats during myocardial ischemia-reperfusion

目的：研究舒芬太尼预处理对大鼠心肌缺血再灌注损伤的影响及PI3K/Akt（P-Akt）信号通路在其中的作用。方法选择健康雄性大鼠60只，体质量250-350 g，随机分为5组：假手术组（Sham组），缺血再灌注组（I/R组），舒芬太尼预处理组（Spc组），舒芬太尼预处理联合PI3K抑制剂组（Spc＋W组），PI3K抑制剂组（W组）。通过结扎大鼠左冠状动脉前降支30 min，松开结扎线复灌120 min制作心肌缺血再灌注模型。Sham组：只挂线，不结扎，持续150 min；I/R组：缺血30 min，再灌注120 min；Spc组：缺血前采用微量注射泵股静脉泵注舒芬太尼1μg/kg，泵注5 min，停止5 min，重复处理3次，总量共3μg/kg的预处理方式，缺血30 min，再灌注120 min；Spc＋Wortmannin组：舒芬太尼预处理前5 min给予PI3K抑制剂（15μg/kg），缺血前30 min舒芬太尼预处理，缺血30 min，再灌注120 min；Wortmannin组：缺血前35 min给予PI3K抑制剂（15μg/kg），缺血30 min，再灌注120 min。于基础状态（T0）、缺血前即刻（T1）、缺血30 min（T2）、再灌注30 min（T3）、再灌注120 min（T4）记录各组大鼠心率和平均动脉压。再灌注末抽取动脉血，离心取血清测定肌酸激酶同工酶（CK-MB）和乳酸脱氢酶（LDH）。实验结束时，各组取6只大鼠心脏测算心肌梗死面积，其余6只大鼠采用Western blot测定心肌组织P-Akt的表达。结果与Sham组比较，I/R组和Spc组P-Akt表达增高（P＆lt;0.01），Spc＋W组和W组P-Akt表达水平差异无统计学意义（P＆gt;0.05）。与I/R组相比，Spc组心肌梗死面积减少（P＆lt;0.01）， CK-MB（P＆lt;0.01）、LDH（P＆lt;0.01）降低，心肌组织P-Akt表达上调（P＆lt;0.01），平均动脉压略有上升，但无统计学差异（P＆gt;0.05）， Spc＋W组和W组梗死面积、CK-MB、LDH差异无统计意义（P＆gt;0.05）。结论舒芬太尼预处理可减轻大鼠心肌缺血再灌注损伤，增加P-Akt的表达，这种保护作用可能与PI3K/Akt信号通路的激活有关。

Objective To study the protective effect of sufentanil preconditioning against myocardial ischemia-reperfusion （I/R） injury and the role of PI3K/Akt signaling pathway. Methods Sixty male SD rats weighing 250-350 g were randomly divided into 5 equal groups, namely the sham-operated group, I/R group, sufentanil preconditioning group （Spc group）, sufentanil preconditioning ＋PI3K inhibitor group （Spc＋W group）, and PI3K inhibitor group （W group）. Myocardial I/R model was established by ligation of the anterior descending branch of the left coronary artery for 30 min followed by reperfusion for 120 min. Sufentanil was administered in 3 doses via the femoral vein before the occlusion, each at 1μg/kg infused within 5 min at a 5-min interval. In Spc＋W and W groups, PI3K inhibitor wortmannin （15 μg/kg） was given intravenously 5 min before sufentanil preconditioning and 35 min before ischemia, respectively. Heart rate and mean arterial pressure （MAP） were continuously monitored during I/R. At the end of reperfusion, blood samples were obtained to determine plasma activation of CK-MB and LDH. Acute infarct size was measured by triphenyltetrazolium chloride staining, and the myocardial tissues were obtained to detect the expression of phosphorylated Akt using Western blotting. Results Phosphorylated Akt expression was significantly up-regulated in I/R and Spc groups as compared with the sham group, and was significantly higher in Spc group than in I/R group. After reperfusion, sufentanil preconditioning significantly decreased myocardial infarct size （P＆lt;0.01） and lowered the levels of CK-MB （P＆lt;0.01） and LDH （P＆lt;0.01） compared with those in the I/R group. The I/R , Spc＋W and W groups showed no significant differences in myocardial infarct size or the levels of CK-MB and LDH. Conclusion The protective effect of sufentanil preconditioning against myocardium against I/R injury in rats may involve PI3K/Akt signaling pathway activation.