Abstract: Objective To investigate the role of P38 inhibitor SB203580 on cerebral edema and Aquaporin 4(AQP4) expression after cerebral ischemia reperfusion in rats. Methods Fifty-four SPF male Sprague-Dawley rats weighing 240-260 g were randomly divided into 3 groups: sham operation group(sham grope); ischemia reperfusion group(I/R group); P38 inhibitor group(SB203580 group).The focal ischemia reperfusion rat model was established by the modified suture method. The rats of I/R group and SB203580 group were exposed to DMSO(10％,400μg/kg) or P38 inhibitor SB203580(400μg/kg) 15 min before suffered from cerebral ischemia. Neurologic function was scored at 24 h reperfusion after 2 h ischemia. HE staining was used to examine brain tissue injury, wet-dry ratio was measured to estimate cerebral edema, Western blot was used to detect the expression of p-P38 and AQP4, RT-PCR was used to detect AQP4mRNA. Results P38 inhibitor SB203580 could improve behavioral scores of ischemic reperfusion rats. The brain water content was decreased after SB203580 treatment compared with I/R group(0.792±0.010 vas 0.817 ± 0.012). The expression of p-P38, AQP4 and AQP4mRNA in margin of infarction of SB203580 group are decreased compared with I/R group compared with I/R group . Conclusion P38 inhibitor SB203580 alleviate the AQP4 expression and cerebral edema in cerebral ischemia reperfusion rats through P38 MAPK pathway.

Key words: Cerebral ischemia reperfusion, cerebral edema, aquaporin 4, p38, SB203580