Prenatal Low-dose X-irradiation Affects Connexins 43 and 26 in Developing Mouse Neocortex

To investigate the effects of low-dose X-irradiation on the expression of connexins (Cxs) in developing cerebral cortex, C57/BL6 pregnant mice were exposed to whole body irradiation of 0.1 Gy and 0.5 Gy, on embryonic day 14.5. Fetal telencephalons, at 1, 3, 12 and 24 hr after exposure, were studied immunohistochemically using anti-Cx43 and Cx26 antibodies, followed by quantitative image analyses. Cx43 expression was significantly reduced in all zones of developing cerebral cortex until 12 hr after exposure, and tended to recover to control level after 24 hr. Cx26 expression was also suppressed in the ventricular zone and cortical plate after irradiation, although it recovered much earlier. Our observations indicate that the expression of Cxs is affected by ionizing radiation during cortical histogenesis.