Influence of environmental enrichment at different stages of development on the expression of p38 in hippocampus of hypoxia-ischemic brain damaged rats

【Objective】 To explore the effects of environmental stimulation on neuronal plasticity and possible mechanisms at different stages of development of hypoxia-ischemic brain damaged(HIBD) postnatal rats. 【Methods】 The Sprague-Dawley(SD) rats' models of HIBD were established by the method of Rice.Then the rats with HIBD were divided randomly into 3 groups:early intervention group,late intervention group and non-intervention group.The sham-operation rats served as sham-operation group.Environmental enrichment intervention was administrated to the early intervention group rats for 20 day since the 2nd day after HIBD.The same intervention to the late intervention group rats since the 23rd after HIBD.On the age of 100 day,the immunohistochemical stain was used to detect the gray values of p38 in hippocampus respectively. 【Results】 Immunohistochemical analysis showed that the expression of p38 in left-sided hippocampus of early intervention group significantly increased as compared with that of late intervention group(P0.01).There was no significant difference between early intervention group and Sham group(P0.05),and the expression of p38 of late intervention group were stronger than that of non-intervention group(P0.05). 【Conclusions】 The neuronal plasticity of early intervention group is promoted more than that of late intervention group.The changes of p38 in their hippocampuses are possibly associated with the influence of environment on neuronal plasticity at different developmental stage of HIBD.