Effects Of Ginkgo Biloba Extract And Progesterone On Expression Of Glucocorticoid Receptor In Cortex Of The Rat After Recurrent Seizures

Objective:To investigate the expression of glucocorticoid receptor(GR) in the cortex of the infantile rats following recurrent seizures and the effects of Ginkgo biloba extract and progesterone on them,and discuss the relationship between GR and developing brain hurt and the protective mechanisms of Ginkgo biloba extract and progesterone on the brain injury.Methods:96 of 7-day-old SD rats were randomly divided into four groups:the control group,the seizure group,the Gink go biloba extract intervention group and the progesterone intervention group.Seizures in rats were induced by inhalant flurothyl daily in six consecutive days. Brain tissue was sampled at different time points(1d,3d,7d)in each group after last seizure.The expression of glucocorticoid receptor proteins in the cortex were detected by immunohistochemistry and Western blot methods.Results:Western blot method was used in comparing the protein expression of glucocorticoid receptor among the three groups in cortex.In the control group,the expression of cytoplasmic GR protein were extensive,the more older the creaser.The expression of cytoplasmic GR protein in the seizure group significantly decreased than those in the control group and the Ginkgo biloba extract intervention group on ARS-3d(PN-15d)andARS-7d(PN-19d)(P＜0.05).Then the expression of cytoplasmic GR protein was no significant difference on ARS-1d(PN-13d)(P＞0.05).The expression of cortical cytoplasm of GR protein in the progesterone intervention group was significantly higher than those in the seizure group on PN-13d(P＜0.05).And on PN-15d,the expression of cytoplasmic GR protein in the seizure group was significantly decreased than those in the control group and the progesterone intervention group(P＜0.05),then the expression of cortical cytoplasm of GR protein was similar on PN-19d(P＞0.05).In immunohistochemistry method showed that there were no significant differences in the expression of GR in the cerebral cortex between the control group and the seizure group on ARS-1d(PN-13d)(P＞0.05).On ARS-3d(PN-15d) and ARS-7d(PN-19d) they were significantly lower than the control group(P＜0.05).Comparing with the seizure group,the expression of GR in the cerebral cortex in the Ginkgo biloba extract intervention group were no significant difference between the two groups on PN-13d(P＞0.05).But on PN-15d and PN-19d they were significantly higher than the seizure group(P＜0.05).The expression of GR in the cerebral cortex in the Progesterone intervention group were significantly higher than the seizure group on PN-13d and PN-15d.Between the two groups was no significant difference(P＞0.05) on PN-19d.Conclusions:①recurrent seizures in neonatal rats modify GR expression in the cortex of rats.This phenomenon raised the possibility that abnormal GR expression might play an important role in developmental brain injury.②The increase of the abnonnal levels of GR in the cortex is probably related to the protective effects of Ginkgo biloba extract and Progesterone on the infantile brain injury induced by seizures.