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 280-320 g, 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.