Research of carbenoxolone on expression of connexin-32 and GFAP in forebrain of epileptic rats

Objective To observe the expression of connexin-32 and glial fibrillary acidic protein (GFAP)and their mutual relationship in forebrain of pentylenetetrazol (PTZ) induced seizure in rats after pretreatment with carbenoxolone (CBX).Methods The animals were divided into normal saline(NS), CBX, PTZ and CBX+PTZ group. The double-labeled fluorescence immunohistochemical staining for anti-GFAP and anti-connexin32 was used to investigate the expression and relation of GFAP positive cells and connexin 32 protein.Results The behavior of seizure in CBX+PTZ group was more serious than that in PTZ group, and the expression GFAP in CBX+PTZ group was also intensified obviously. Noticeably, the expression of GFAP in CBX group was much higher than that in NS group. The distribution of Cx32 in cortex, hippocampus and amygdaloid nucleus increased in PTZ-induced epileptic rats, but Cx32 decreased in CBX+PTZ group. On the slices with anti-Cx32 and anti-GFAP double-labeled, anti-Cx32 positive production was close to anti-GFAP positive astrocytes. The GFAP positive astrocytes increased obviously, but the expression of Cx32 decreased in CBX+PTZ group.Conclusion The present results indicate that epilepsy enhancemented by CBX pretreatment may be related to astrocytic hyperplasia and the decreased expression of Cx32 protein.