Mechanism of exogenous hydrogen sulfide-induced reduction of apoptosis in neurons during focal cerebral ischemia-reperfusion in rats: PINK1/Parkin pathway-mediated mitochondrial autophagy / 中华麻醉学杂志

ABSTRACT

Objective:To investigate the relationship between the mechanism of exogenous hydrogen sulfide (H 2S)-induced reduction of apoptosis in neurons during focal cerebral ischemia-reperfusion (I/R) and PINK1/Parkin pathway-mediated mitochondrial autophagy in rats. Methods:Two hundred and sixteen healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 250-270 g, were divided into 4 groups ( n=54 each) using a random number table method: control group (group C), I/R group, H 2S group and H 2S plus 3-methyladenine (3-MA) group (H 2S+ 3-MA group). Focal cerebral ischemia was induced by middle cerebral artery occlusion in anesthetized rats.In group H 2S+ 3-MA, 3-MA 10 mg/kg was intraperitoneally injected at 15 min before the onset of reperfusion, while the equal volume of normal saline was given instead in the other groups.In H 2S and H 2S+ 3-MA groups, 0.25% NaSH (a donor of exogenous H 2S) 10 mg/kg was intraperitoneally injected at the onset of reperfusion, while the equal volume of normal saline was given instead in the other groups.At 1, 3 and 7 days of reperfusion, neural function was scored, and corner test (the percentage of left turn was calculated) was performed.Brains were removed and brain tissues were obtained for determination of the cerebral infarct size, Bax, Bcl-2 and caspase-3 positive cells, cell apoptosis, and expression of mitophagy-related protein microtubule-associated protein 1 light chain 3 (LC3), PINK1 and Parkin (by Western blot). The percentage of cerebral infarct size, rate of Bax, Bcl-2 and caspase-3 positive cells and apoptosis rate were calculated.The ratio of LC3-Ⅱexpression to LC3-Ⅰexpression (LC3-Ⅱ/LC3-Ⅰ) was also calculated. Results:Compared with group C, the neural function score was significantly decreased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax, Bcl-2 and caspase-3 positive cells, apoptosis rate of neurons, and LC3-Ⅱ/LC3-Ⅰ were increased, and the expression of PINK1 and Parkin was up-regulated at each time point of reperfusion in group I/R ( P<0.05). Compared with group I/R, the neural function score and rate of Bcl-2 positive cells were significantly increased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax and caspase-3 positive cells, and apoptosis rate of neurons were decreased, the expression of PINK1 and Parkin was up-regulated, and LC3-Ⅱ/LC3-Ⅰ were increased at each time point of reperfusion in group H 2S ( P<0.05), and no significant change was found in the parameters mentioned above in group H 2S+ 3-MA ( P>0.05). Compared with group H 2S, the neural function score and rate of Bcl-2 positive cells were significantly decreased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax and caspase-3 positive cells, and apoptosis rate of neurons were increased, the expression of PINK1 and Parkin was down-regulated, and LC3-Ⅱ/LC3-Ⅰ was decreased at each time point of reperfusion in H 2S+ 3-MA group ( P<0.05). Conclusion:The mechanism by which exogenous H 2S inhibits apoptosis in neurons during focal cerebral I/R is related to enhancing mitochondrial autophagy mediated by the PINK1/Parkin pathway in rats.