Potential teratogenic effect of prenatal dexamethasone administration on palate development: Experimental study in rats

The interaction of cell populations and synchronization of cell signaling pathways during craniofacial development can cause malformations such as facial clefts when interrupted by teratogenic agents including synthetic corticosteroids. Therefore, this study aimed to determine the potentially disturbing dexamethasone (Dex) effect on palatal shelf development in rat embryos and the possible reasons for this teratogenic potential in relation to fibroblast growth factor 10 (FGF10) as well as FGF10 receptor2 (FGFR2) signaling. Thirty pregnant rats were used, which were then randomly categorized into three groups of ten animals each: the control group, where pregnant rats received no treatment, Sham group in which pregnant rats were injected subcutaneously with saline (0.4 mg/kg body weight) during the mid-pregnancy period at gestational day 9–14, and Dex-treated group, where pregnant rats received 0.4 mg/kg of Dex at mid-gestational period. Pregnant animals from all groups were sacrificed on day 20 of gestation before birth and the fetuses were removed for examination of the palatal shelves using a light microscope (LM). In addition, a real-time polymerase chain reaction and a reverse transcription-polymerase chain reaction (RT-PCR) were done to evaluate FGF10 and its receptor FGFR2 gene expression. The cleft palate incidence rates in the groups of embryos were determined. Only the offspring in the Dex group showed a cleft palate. Moreover, the cleft palate incidence rate in the Dex group was significantly different compared to controls. Moreover, a significant decrease in FGF10 and FGFR2 expression levels was reported in the Dex group than in the controls. Dex treatment in mid-gestation may increase the incidence of cleft palate development, which may be due to modulation of FGF signaling. This calls for caution when using this medication in the first half of pregnancy unless absolutely necessary and under close medical supervision. • Cleft palate can develop in association with decreased FGF10 and FGFR2 in fetuses of pregnant rats treated with dexamethasone.