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The present study was undertaken to study the effects of exogenous hydrogen sulfide (H(2)S) on global cerebral ischemia-reperfusion(I/R) and the underlying mechanisms. After a 24h I/R, administration of NaHS, an exogenous donor for H(2)S, at the dose of 0.2 or 0.4 μmol/kg significantly decreased the apoplexy index, neurological symptom scoring, and brain infarcted area as compared to the I/R group in a dose dependent manner. At the same time, NaHS-treated rats displayed significant reduction of MDA content, and striking increase of SOD activity in the brain tissues compared with I/R group. The up-regulated mRNA levels of p47(phox) and gp91(phox) subunits of NADPH oxidase were also suppressed by NaHS treatment. In this study, the pro-inflammatory markers TNF-α and MCP-1 in I/R group were markedly increased by 24h I/R, which were significantly attenuated by NaHS in a dose-dependent manner. In contrast, the anti-inflammatory factor IL-10 was markedly induced by NaHS administration. In addition, the expression of the anti-apoptotic protein Bcl-2 was significantly decreased in I/R group compared with the sham-operated group. This reduction was significantly blunted in NaHS-treated group. On the contrary, the pro-apoptotic protein Bax content in brain tissues of I/R group was markedly elevated compared with sham-operated animals. And such an induction of Bax content was significantly ameliorated by NaHS. Taken together, our results suggest that hydrogen sulfide has potent protective effect against a severe cerebral injury induced by a global I/R possibly through the inhibition of oxidative stress, inflammation and apoptosis., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Excessive mitochondrial fission activation has been implicated in cerebral ischemia-reperfusion (IR) injury. Hypothermia is effective in preventing cerebral ischemic damage. However, effects of hypothermia on ischemia-induced mitochondrial fission activation is not well known. Therefore, the aim of this study was to investigate whether hypothermia protect the brain by inhibiting mitochondrial fission-related proteins activation following cerebral IR injury. Adult male C57BL/6 mice were subjected to transient forebrain ischemia induced by 15 min of bilateral common carotid artery occlusion (BCCAO). Mice were divided into three groups (n=48 each): Hypothermia (HT) group, with mild hypothermia (32–34 °C) for 4 h; Normothermia (NT) group, similarly as HT group except for cooling; Sham group, with vessels exposed but without occlusion or cooling. Hematoxylin and eosin (HE), Nissl staining, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and behavioral testing (n=6 each) demonstrated that hypothermia significantly decreased ischemia-induced neuronal injury. The expression s of Dynamin related protein 1 (Drp1) and Cytochrome C (Cyto C) (n=6 each) in mice hippocampus were measured at 3, 6, 24, and 72 h of reperfusion. IR injury significantly increased expressions of total Drp1, phosphorylated Drp1 (P-Drp1 S616) and Cyto C under normothermia. However, mild hypothermia inhibited Drp1 activation and Cyto C cytosolic release, preserved neural cells integrity and reduced neuronal necrosis and apoptosis. These findings indicated that mild hypothermia-induced neuroprotective effects against ischemia-reperfusion injury is associated with suppressing mitochondrial fission-related proteins activation and apoptosis execution. [ABSTRACT FROM AUTHOR]