Effects of mild hypothermia on the expression of Dickkopf-1 in rats' brains after focal cerebral ischemia and reperfusion / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the effects of mild hypothermia on the expression of Dickkopf-1(Dkk1)in rats'brains after focal cerebral ischemia and reperfusion and to explore the molecular mechanism of any neuroprotective effects of mild hypothermia. Methods A focal cerebral ischemia and reperfusion model was established in rats by intraluminal filament occlusion of the middle cerebral artery.The adult rats were randomly divided into four groupsa sham-operation group,a sham-operation plus mild hypothermia group,a model group,and a model plus mild hypothermia group.The expression of Dkk-1 mRNA and protein in the ischemic cortex at different phases afterreperfusion were assessed using a reverse transcription polymerase chain reaction(RT-PCR),Western blotting and immunohistochemical staining.Results There was little expression of Dkk-1 mRNA or its protein in the sham-operation group or in the sham-operation plus mild hypothermia group.Expression of Dkk-1 mRNA and its protein began to increase after 2 h of cerebral ischemia and 3 h of reperfusion,with expression peaking at the 24th h after the start of reperfusion and then decreasing markedly.But expression was still stronger than in the sham-operation group at the 72nd h.At every reperfusion time point,expression of Dkk-1 mRNA and its protein were markedly less in the model plus mild hypothermia group than in the model group. Conclusion Dkk-1 probably participates in the pathologic process of injury caused by focal cerebral ischemia and reperfusion.Inhibiting the expression of Dkk-1 after focal cerebral ischemia and reperfusion is partly responsible for the neuroprotective effects of mild hypothermia.