舒芬太尼后处理对犬心肌缺血／再灌注Bcl-2、Bax的影响及其与JAK2-STAT3信号通路的关系

Effects of sufentanil postconditioning on myocardial ischemiaJreperfusion injury in dogs and its relationship to the JAK2- STAT3 signaling pathway

目的研究舒芬太尼后处理对心肌缺血，再灌注损伤（ischemia／reperfusioninjury，I／RI）细胞凋亡的影响以及与信号通路JAK2-STAT3的关系。方法健康杂种家犬24只，体重10kg-15kg，按随机数字表法分为4组（每组6只）：假手术组（Sham组，只穿线，不结扎），心肌缺血厢罐注（ischemia／reperfusion，I／R）组，舒芬太尼后处理组（spo组，于再灌注前5min静脉注射舒芬太尼0．6μg／kg），舒芬太尼后处理＋AG490组（SPO＋AG490组，于再灌注前5min静脉注射1ms／ksAG490，特异性的JAK2抑制剂），除Sham组外，所有犬心脏都经历30min缺血和120min再灌注。再灌注120min时，取各组缺血区心肌组织，采用末端脱氧核苷酸转移酶介导的dUTP原位切口末端标记（terminaldeoxynucleotidyltransferase-mediateddUTPnick-endlabeling，TUNEL）法测定心肌细胞的凋亡情况，免疫组化法测定各组Bcl-2、Bax以及磷酸化STAT3（p-ATAT3）蛋白的表达，并计算Bel-2和Bax表达的比值（Bel-2／Bax）。结果再灌注120min时，可在I／R组缺血区心肌组织中检测到大量凋亡心肌细胞（63．9-,-4．0）％，而舒芬太尼后处理显著降低心肌细胞凋亡指数（30．7＋1．5）％；与Sham组比较，I／R组、SPO组和SPO＋AG490组Bcl-2与Bax表达上调，I／R组Bel-2／Bax比值降低，SPO组Bcl-2／Bax比值升高；舒芬太尼后处理使P-STAT3表达明显增加，特异性的阻断剂AG490抑制了舒芬太尼后处理对心肌I／RI凋亡的作用，即抑制p-STAT3表达的增加。结论舒芬太尼后处理对心肌I／RI细胞凋亡有一定的抑制作用，通过激活JAK2-STAT3信号转导通路上调Bcl-2蛋白和下调Bax蛋白来发挥作用。

Objective To investigate the anti-apoptotic effects of sufentanil postconditioning on myocardial ischemia/ reperfusion injury （I/RI） and its relationship to the JAK2-STAT3 signaling pathway. Methods Twenty-four dogs were randomly divided into 4 groups： sham-operation group（group Sham）, ischemia/reperfusion group（group I/R）, sufentanil posteonditioning＋I/R group（group SPO）, AG490±sufentanil postconditioning＋I/R group（group SPO＋AG490）. Except sham group, all dogs subjected to 30min of myocardial ischemia followed by 120 min of reperfusion. After reperfusion 2 h, the presence of apoptosis was determined quantitively by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling（TUNEL） methods, immunohistochemistry was used to detect the Bcl-2, Bax, p-STAT3 and protein of myocardial tissue. Results A significant number of TUNEL positive cells [ （63.9±4.0）% ] were observed in myocardial tissue from hearts subjected to 30 rain of myocardial isehemia followed by 120 min of reperfusion. Administration of sufentanil exerted a significant anti-apoptotic effect that has been conformed by reduced TUNEL- positive staining [ （30.7±1.5）% ]. Compared with the group Sham, expression of Bcl-2 and Bax is increased in myocardial group I/R, group SPO and group SPO＋AG490. Bel-2/Bax ratio is lower in group I/R and higher in group SPO; P-STAT3 activity was increased in the myocardial tissue after sufentanil postconditioning compared with that in group Sham （P〈0.05）. Conclusions Sufentanil postconditioning provided myocardial protection to I/RI on dogs, the mechanism of myocardial protection is related to the inhibition of cell apoptosis via up-regulation of Bel-2 expression and down-regulation Bax expression.