ABSTRACT
Objective To investigate whether ROS/JNK/Egr-1 signaling pathway was activated in cardiomyocytes after hypoxia/reoxygenation ( H/R).Methods H9c2 cardiomyocytes were grouped randomly as follows: control group, H/R group, control +the ROS donor xanthine oxidase /hypoxanthine (XO/HX) group, H/R +the ROS scavenger edaravones (EDA) group, H/R +the ROS scavenger N-acetyl-L-cysteine (NAC) group, H/R +JNK inhibitor SP60012 group.To establish H9c2 H/R models and the myocardial cells were treated with different concentrations of EDA (2 × 10 -6,2 ×10 -5,2 ×10 -4 M), NAC (5 ×10 -4,2 ×10 -3,8 ×10 -3 M), XO/HX (1mU/mL/1.2 ×10 -4 M , 3mU/mL/3.6 ×10 -4 M, 5mU/mL/6.0 × 10 -4 M) and SP600125 (2 ×10 -5 M).ROS level was measured by flow cytometry, and Egr-1, p-JNK and total JNK protein levels were detected by Western blot.ResuIts ROS levels and Egr-1 protein levels in H/R group were significantly higher than control group (P<0.05).The moderate and high concentrations EDA and NAC of ROS scavenger significantly decreased the high levels of ROS and Egr-1 protein ( P<0.05 ) , but there were no significant differences of low concentration.There was a significant positive correlation between ROS levels and Egr-1 protein (r=0.91,P<0.01).JNK activation levels in each concentrations of XO/HX were significantly higher than control group, and JNK activation increased with the increasing of XO/HX concentrations (P<0.05).JNK activation level in H/R group was higher than control group, after treated by EDA and NAC of ROS scavenger and JNK inhibitor, JNA activation reduced (P<0.05).Egr-1 protein levels in H/R group was higher than that in control group, and JNK inhibitor reduced the expression of Egr-1 protein induced by H/R.ConcIusion H/R activates ROS/Egr-1 signaling pathway in H9c2 cardiomyocytes, and JNK activation plays an important role in this pathway.