Glucocorticoid receptor expression in neonatal rat cortex following recurrent seizures The role in developing brain injury

BACKGROUND: Studies have explored changes in neonatal rat glucocorticoid receptor (GR) expression changes following mature brain injury. OBJECTIVE: To investigate the temporal and special changes of GR during brain development in rats with recurrent seizures. DESIGN, TIME AND SETTING: A randomized, controlled animal experiment was performed at the Department of Pediatrics, Second Xiangya Hospital of Central South University, from February 2008 to March 2009. MATERIALS: Rabbit anti-rat GR monoclonal antibody was purchased from Santa Cruz Biotechnology, USA; goat anti-rabbit IgG was purchased from Zhongshan Goldenbridge Biotechnology, China. METHODS: A total of 48 Sprague-Dawley rats, 7 days old, were randomly assigned to control and seizure groups, with 24 animals in each group. Seizures were induced by inhalant flurothyl. MAIN OUTCOME MEASURES: Changes in GR protein expression in the rat cerebral cortex were detected by Western blotting analysis and immunohistochemistry. RESULTS: GR expression in the cerebral cortex of control rats significantly increased with aging (P < 0.05), and varied in the frontal lobe, temporal lobe, and parietal lobe. GR was predominantly expressed in the cytoplasm early and rapidly increased in the nuclei. GR protein expression in the cerebral cortex after seizure was lower in the cytoplasm at 15 days and in nuclear protein at 19 days. CONCLUSION: GR expression displayed temporal and spatial changes in brain development. Recurrent seizures in neonatal rats cause abnormal GR expression and might play an important role in developing brain injury.