Effect of hydrogen-rich saline on expression of miR-210 and miR-21 in hippocampus during global cerebral ischemia-reperfusion in rats

Objective To evaluate the effects of hydrogen-rich saline on the expression of miR-210 and miR-21 in hippocampus during global cerebral ischemia-reperfusion (I/R) in rats.Methods Seventy-two healthy male Sprague-Dawley rats,aged 9-10 weeks,weighing 250-300 g,were randomly divided into 3 groups (n =24 each):sham operation group (group S),group I/R,and hydrogen-rich saline group (group H).Global cerebral I/R was produced by 4-vessel occlusion method.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 of hydrogen-rich saline in the other two groups.Rats were sacrificed at 24 and 72 h of reperfusion,and then the bilateral hippocampi were removed for detection of the expression of miR-210 and miR-21 using RT-PCR.The global brain tissues were also obtained and stained with HE for examination of the changes in pyramidal cells in the CA1 region of hippocampus.Results Compared with group S,the expression of miR-210 and miR-21 was significantly up-regulated,and the number of pyramidal cells was decreased in group I/R (P ＜ 0.05).Compared with group I/R,the expression of miR-210 and miR-21 was significantly down-regulated,and the number of pyramidal cells was increased in group H (P ＜ 0.05).The pathological changes were significantly ameliorated in group H.Conciusion The mechanism by which hydrogen-rich saline attenuates global cerebral I/R injury is related to downregulation of the expression of miR-210 and miR-21 in rat hippocampus. Key words: Hydrogen; MicroRNAs; Reperfusion injury; Brain;  Hippocampus