Effect of mild hypothermia on expression of hippocampal microRNA-210 during global cerebral ischemia-reperfusion in rats

Abstract

Objective To evaluate the effect of mild hypothermia on expression of hippocampal microRNA-210 (miR-210) during global cerebral ischemia-reperfusion (I/R) in rats.Methods Sixty healthy male Sprague-Dawley rats,aged 9-10 weeks,weighing 280-320g,were randomly divided into 3 groups (n =20 each):sham operation group (group S),group I/R,and mild hypothermia group (group H).Ventricular fibrillation (VF) was induced with transoesophageal cardiac pacing followed by cardiopulmonary resuscitation to establish the global cerebral I/R model.In group H,the rectal temperature was cooled down to 32-34 ℃ by rubbing body surface with ethanol within 10 min starting from onset of reperfusion and maintained at this level for 6 h.In the other groups,the rectal temperature was maintained at 36-37 ℃ with a heating blanket.Rats were sacrificed at 24 h of reperfusion,and then the bilateral hippocampi were removed for detection of miR-210 expression (using RT-PCR) and apoptosis (by TUNEL).Results Compared with group S,the expression of miR-210 was up-regulated,and apoptosis rate was increased in group I/R.Compared with group I/R,the expression of miR-210 was down-regulated,and apoptosis rate was decreased in group H.Conclusion Mild hypothermia playes a role in cerebral resuscitation possibly by down-regulating miR-210 expression and reducing apoptosis in hippocampal cells of rats. Key words: MicroRNAs; Hypothermia, induced; Brain; Reperfusion injury; Hippocampus