Effect of hydrogen-rich saline on regulatory T cells in peripheral blood during global cerebral ischemia-reperfusion in rats

Objective To evaluate the effect of hydrogen-rich saline on the regulatory T cells （Tregs ） in the peripheral blood during global cerebral ischemia-reperfusion （I/R ） in rats .Methods Seventy-seven male Sprague-Dawley rats ,aged 2-3 months ,weighing 260-300 g ,were randomly divided into 3 groups using a random number table：sham operation group （group S , n=11） ,group I/R （n=33） ,and hydrogen-rich saline group （group H , n=33 ） .Global cerebral I/R was produced by 4-vessel occlusion method .The bilateral carotid arteries were blocked for 15 min followed by reperfusion in I/R and H groups .In group H ,0.6 mmol/L hydrogen-rich saline 5 ml/kg was injected intraperitoneally at 0 and 6 h of reperfusion ,while the equal volume of normal saline was injected instead in the other two groups .Before ischemia （T0 ） in group S and at 6 ,24 and 72 h of reperfusion （T1-3 ） in I/R and H groups ,7 rats were chosen ,the blood samples from the peripheral vein were collected for determination of the number of Tregs . Then the animals were sacrificed and the spleen was removed for measurement of transforming growth factor-β1 （TGF-β1） content .The left 4 rats of each group were sacrificed at T0 and T1-3 and the brains were obtained for examination of the pyramidal cell morphology in the hippocampal CA 1 region and for determination of the number of pyramidal cells in brain tissues .Results Compared with group S , the number of pyramidal cells in the hippocampal CA1 region ,the number of Tregs in the peripheral blood and content of TGF-β1 in the spleen were significantly decreased at T1-3 in group I/R （ P〈0.05） .Compared with＆nbsp;group I/R ,the number of pyramidal cells in the hippocampal CA 1 region and the number of Tregs in the peripheral blood at T2-3 ,and the content of TGF-β1 in the spleen at T1-3 were significantly increased （ P〈0.05） ,and the pathological changes of pyramidal cells were attenuated in group H .Conclusion The mechanism by which hydrogen-rich saline attenuates global cerebral I/R injury may be related to the increased number of Tregs in peripheral blood and promoted secretion of TGF-β1 in rats . Key words: T-lymphocytes,regulatory; Hydrogen; Reperfusion injury; Brain