Abstract: Objective To investigate the role of HMGB1 involved in the activation of p38MAPK signal pathway in the hippocampus of rats after cardiopulmonary resuscitation. Method Rats were randomly divided into two groups as shame-operated group, CPR group including 2, 6, 12, 24 and 48 h after restoration of spontaneous circulation( ROSC) (5sub-groups).The animals were sacrificed and hippocampus were removed at the indicated time. Pathological changes were observed at each time point. Calculated the brain water content by day/wet ration.The HMGB1mRNA expression was detected by RT-PCR technique. The expressions of HMGB1 and p38MAPK activity were determined using Western blot. Results There were no histopathological in the hippocampus of rats in shame-operated group, brain tissue appeared change of ischemia pathology in CPR group, it was the most severest at ROSC 24 h. The brain water content, HMGB1mRNA in rats of CPR group increased obviously along with the prolongation of time following ROSC and reached its peak at ROSC 24 h(P<0.01),much higher than that of shame-operated group, the HMGB1 level in the hippocampus of rats after CPR significantly declined at 2 h after ROSC(P<0.01) and increased obviously at 6, 12 h and reached peak 24 h later(P<0.01), the p38MAPK activity in the hippocampus of rats after CPR, significantly increased at 2 h after ROSC and reached peak 6 h later(P<0.01), then declined slowly later, much higher than that of shame-operated group. Conclusions HMGB1 involved in the activation of p38 MAPK signal pathway that may play an important role in the early stages of brain injury after CPR.

Key words: Cardiopulmonary resuscitation, HMGB1, p38MAPK, Neuroinflammation