Comparative effects of dexamethasone on gravid uteri histology and immunoreactivity in sheep and goats

Abstract

Introduction: Dexamethasone treatment greatly improves foetal and maternal survival. However, it causes a decrease in birth weight which has been attributed to decreasing placental functions. In addition to placental role in foetal nutrition, uterine cells secretions play important role in foetal nutrition. The uterine cell development is regulated by progesterone receptor (PR). This study investigated comparative effects of dexamethasone on gravid uteri histology and immunoreactivity in ovine and caprine species. Methods: Sixteen Sahel does and 2 bucks; and 16 Yankasa ewes and 2 rams were used for this study. Dexamethasone injections were administered at 0.25 mg/kg body weight on days 1, 3 and 5 during first trimester, and day 51, 53 and 55 during second trimester. Uterine biopsies were harvested at days 28 and day 78 of gestation for histological and immunohistochemical analysis. Results: Endometrial glands were down-regulated, while PR were up regulated by dexamethasone in both species with more severe effects in sheep compared to goats. The down-regulation of the endometrial glands contributed, to the decrease in birth weight commonly reported to be associated with dexamethasone treatment. Significance: Dexamethasone decreased uterine epithelial proliferation in both species, but more severe in sheep. The decrease in endometrial glands proliferation has the potential to reduce uterine secretions and influence absorption of stratum functionale. The use of dexamethasone might lead to foetal growth retardation and decrease neonatal weight. The differences in uterine responses between the sheep and goats suggest species difference in response to dexamethasone treatment.