Correlative study of autophagy flux and hydrogen sulfide postconditioning protecting on type 2 diabetic rats with myocardial ischemia reperfusion injury

Abstract

Objective To investigate the correlative of autophagy flux and hydrogen sulfide postconditioning protecting against myocardial ischemia reperfusion (I/R) injury in type 2 diabetic rats in vivo. Methods Sixty adult male Sprague-Dawley rats were randomly divided into five groups (n=12): sham group, I/R group, chloroquine (CQ) group, sodium hydrosulfide (NaHS) group and CQ + NaHS group. Rats in the sham group only gave thoracotomy and separation of the left anterior descending coronary artery; In the I/R group rats were occluded the left anterior descending coronary artery for 30 min, followed by 4 h of reperfusion; In the CQ group rats received CQ 10 mg/kg by intraperitoneal injection at 1 h before the I/R operation; In the NaHS group rats were injected NaHS 0.05 mg/kg intravenously within 1 min after releasing the left anterior descending coronary artery undergoing 30 min occlusion, then followed by 4 h of reperfusion; and in the CQ + NaHS group rats received CQ 10 mg/kg by intraperitoneal injection at 1 h before the I/R operation additionally on the basis of NaHS group. The heart rate, mean arterial pressure and rate-pressure product (RPP) were detected and recorded at 15 min of balance period, ischemic period, and 1, 2, 4 h after reperfusion. After reperfusion for 4 h, the rats were sacrificed and the hearts were used to calculate the range of myocardial infarction and the express of microtubule-associated protein 1 light chain 3 (LC3), Cathepsin B, Beclin-1 and P62 were determined by Western blotting. Results The heart rates in the five groups had no siginficant differences at each time point (F=0.854, P=0.512), but the mean arterial pressure and RPP showed siginficant differences among the five groups at each time point (F=5.182, P=0.007; F=5.082, P=0.008). Furthermore, the mean arterial pressure[(87 ± 8) mmHg vs. (72 ± 10) mmHg, (91±10) mmHg vs. (63 ± 6) mmHg] and RPP [(35.4 ± 4.6)·103 mmHg·beat/min vs. (28.7 ± 5.8)·103 mmHg·beat/min, (36.2 ± 5.8)·103 mmHg·beat/min vs. (26.8 ± 3.8)·103 mmHg·beat/min] in the NaHS group at 2, 4 h after reperfusion were much higher than those in the I/R group (all P<0.05). The range of myocardial infarction and the express of LC3, Cathepsin B, Beclin-1 and P62 at 4 h after reperfusion all had statistical significance obviously among five groups (F=96.907, 71.164, 43.594, 57.180, 35.967, all P<0.05) , and above indicators in the NaHS group were much lower than those in the I/R group, CQ group and CQ + NaHS group (all P<0.05). Conclusion Hydrogen sulfide postconditioning play a protective role through repairinng autophagy flux in type 2 diabetic rats with I/R injury. Key words: Hydrogen sulfide; Ischemic postconditioning; Myocardial reperfusion injury; Diabetes mellitus, type 2; Autophagy; Rats