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

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 postconditioning+I/R group(group SPO),AG490+sufentanil postconditioning+I/R group(group SPO+AG490).Except sham group,all dogs subjected to 30 min 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 min of myocardial ischemia 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.Bcl-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 Bcl-2 expression and down-regulation Bax expression. Key words: Ischemia/reperfusion injury;  Postconditioning;  Apoptosis;  JAK2-STAT3