Enhanced expression of glial fibrillary acidic protein in the hippocampus one month after whole brain irradiation of adult rats.

OBJECTIVE To examine the changes of glial fibrillary acidic protein in the hippocampus after whole brain irradiation of adult rats. METHODS Forty-one male Sprague-Dawley rats (180-220 g weight and 6-8 weeks) were divided into the 9 irradiation subgroups, sham, and control groups. Their whole brain was irradiated by a single dose of 2, 10, and 30 Gy. At one day, one week, and one month after irradiation, reverse transcriptase-polymerase chain reaction assay was used to semiquantitatively analyze the expression of glial fibrillary acidic protein messenger RNA, and immunohistochemistry was performed to detect glial fibrillary acidic protein-positive cells. This study was carried out at The Second Affiliated Hospital of Soochow University, Jiangsu, China between October 2008 and November 2009. RESULTS No obvious changes were found between the control and 2 Gy irradiation groups. However, glial fibrillary acidic protein messenger RNA levels were increased after one day and reached a higher level one month after 10 and 30 Gy irradiation. A significant increase in glial fibrillary acidic protein-positive astrocytes was detected one month after 30 Gy irradiation. CONCLUSION Astrocytes may play an important role in the mechanisms underlying radiation-induced brain injuries in the early stages.