Maternal treatment with glucocorticoids modulates gap junction protein expression in the ovine fetal brain

Abstract Gap junctions facilitate intercellular communication and are important in brain development. Connexins (Cx) comprise a transmembrane protein family that forms gap junctions. Cx-32 is expressed in oligodendrocytes and neurons, Cx-36 in neurons, and Cx-43 in astrocytes. Although single antenatal steroid courses are recommended for fetal lung maturation, multiple courses can be given to women at recurrent risk for premature delivery. We examined the effects of single and multiple glucocorticoid courses on Cx-32, Cx-36, and Cx-43 protein expressions in the fetal cerebral cortex, cerebellum, and spinal cord, and differences in Cx expression among brain regions under basal conditions. In the single-course groups, the ewes received dexamethasone (6 mg) or placebo as four intramuscular injections every 12 h over 48 h. In the multiple-course groups, the ewes received the same treatment, once a week for 5 weeks starting at 76–78 days of gestation. Cx were measured by Western immunoblot on brain samples from 105 to 108-day gestation fetuses. A single dexamethasone course was associated with increases ( P