Effect of hydrogen on mitochondrial membrane potential during focal cerebral ischemia-reperfusion in rats

Abstract

Objective To investigate the effect of hydrogen on mitochondrial membrane potential during focal cerebral ischemia-reperfusion (I/R) in rats. Methods Eighty-four healthy adult male SPF Sprague-Dawley rats, weighing 220-240 g, were divided into 3 groups (n=28 each) using a random number table: sham operation group (Sham group), I/R group and hydrogen group (H2 group). Focal cerebral I/R was produced by mid-cerebral artery occlusion in I/R and H2 groups.Hydrogen 10 ml/kg was intraperitoneally injected immediately after onset of reperfusion and at 12 h of reperfusion in group H2.Neurological deficit was scored at 24 h of reperfusion.The rats were then sacrificed and brain tissues in cortex were removed for microscopic examination of the pathological changes and for determination of cerebral infarct size (by TTC staining), nerve cell apoptosis (by TUNEL), mitochondrial membrane potential(by JC-1 staining) and expression of Bcl-2 and Bax (by Western blot). Apoptotic index (AI) was calculated. Results Compared with Sham group, the neurological deficit score, percentage of cerebral infarct size and AI were significantly increased, the mitochondrial membrane potential was decreased, Bax expression in brain tissues was up-regulated, and Bcl-2 expression in brain tissues was down-regulated in I/R and H2 groups (P<0.05). Compared with I/R group, the neurological deficit score, percentage of cerebral infarct size and AI were significantly decreased, the mitochondrial membrane potential was increased, Bax expression in brain tissues was down-regulated, and Bcl-2 expression in brain tissues was up-regulated (P<0.05), and the pathological changes of brain tissues were significantly attenuated in H2 group. Conclusion The mechanism by which hydrogen reduces focal cerebral I/R injury is related to decreasing dissipation of mitochondrial membrane potential and inhibiting nerve cell apoptosis in rats. Key words: Hydrogen; Reperfusion injury; Brain; Membrane potential, mitochondrial