Effect of mild hypothermia on the immunoreactivity of MAP_2 after focal cerebral ischemia in rats

Objective To observe the effect of mild hypothermia on the immunoreactivity of microtubule associated protein 2 (MAP 2) after focal cerebral ischemia/reperfusion, and to investigate the relationship between MAP 2 changes and the neuroprotection of mild hypothermia.Methods The focal cerebral ischemia/reperfusion models of rats were achieved by middle cerebral artery occlusion (MCAO). The adult rats were randomly divided into sham operation group, normothermia ischemia/reperfusion group and hypothermia ischemia/reperfusion group. The two ischemic groups were respectively further divided into 3 subgroups (subjected ischemia for 2h, 6h, 12h respectively and then all reperfused for 4h, n =7 per time point). Brain mild hypothermia was achieved 30 minutes after ischemia and maintained to reperfusion period. The neurological deficit scores were determined before killing, pathohistological changes of injured neurons were demonstrated by H E staining and microscopy, and the expression of MAP 2 was assayed by immunohistochemistry and computerized image analysis system.Results Compared with the normothermia group, mild hypothermia greatly decreased the neurological deficit scores (P0.05 or P0.01), obviously attenuated the pathological injury of neurons, and increased the expression of MAP 2 in penumbra significantly (P0.01).Conclusion Mild hypothermia can greatly attenuate neuronal damage through enhancing MAP 2 expression in penumbra after focal cerebral ischemia/reperfusion.