Effect of isoflurane on myocardial ischemia-reperfusion injury through the p38 MAPK signaling pathway.

OBJECTIVE: To investigate the effect of isoflurane on myocardial ischemia-reperfusion injury through the p38 mitogen-activated protein kinase (MAPK) signaling pathway.

MATERIALS AND METHODS: A total of 36 specific-pathogen-free (SPF) Sprague-Dawley rats were randomly divided into sham group (n=12), model group (n=12) and isoflurane group (n=12). In model group and isoflurane group, the myocardial ischemia-reperfusion injury model was established via the ligation of left anterior descending coronary artery (ischemia for 30 min and reperfusion for 3 h). In sham group, the left anterior descending coronary artery was not ligated, but the chest was opened and threaded using the same method. After ischemia, the rats in isoflurane group were inhaled with isoflurane. The cardiac function of rats in each group was detected before ischemia (T0) and once every 2 h after reperfusion (T1-T4) for a total of 5 times, and the cardiac function indexes included ejection fraction (EF), fractional shortening (FS), left ventricular systolic pressure (LVSP) and left ventricular end-diastolic pressure (LVEDP). After the rats were executed, the myocardial infarction tissues were taken for hematoxylin-eosin (HE) staining and 2,3,5-triphenyltetrazolium chloride (TTC) staining to observe the morphological changes in tissues and the degrees of myocardial ischemia and infarction. The malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in myocardial cells in the infarction site in each group were detected using the MDA and SOD kits. Moreover, the expression levels of related proteins in the p38 MAPK signaling pathway in myocardial cells in the infarction site were detected via Western blotting.

RESULTS: In model group, the cardiac function was significantly damaged (p<0.01), there was significant pathological damage in the myocardium, the area of myocardial infarction was significantly increased (p<0.01), the MDA content was significantly increased (p<0.01), the SOD activity declined obviously (p<0.01), and the expression levels of p-p38 and p-tau protein were significantly increased (p<0.01) compared with those in control group. After intervention with isoflurane, the cardiac function of rats was significantly improved (p<0.01), the pathological damage in myocardial tissues was alleviated, the area of myocardial infarction was reduced (p<0.01), the MDA content declined (p<0.01), the SOD activity was increased (p<0.01), and the expression levels of p-p38 and p-tau protein were decreased (p<0.01).

CONCLUSIONS: Isoflurane can, through inhibiting the p38 MAPK signaling pathway, effectively protect the cardiac function of rats from myocardial ischemia-reperfusion injury, reduce the area of myocardial infarction, alleviate the pathological damage in myocardial cells and reduce the oxidative stress response.