Prenatal dexamethasone exposure affects mandibular bone and tooth development in rats

Prenatal corticosteroids exposure is associated with important adverse effects on fetuses development. In this study histomorphometric evaluation of the mandibular bone and mandibular first molar from fetuses exposed to exogenous glucocorticoid in the final period of pregnancy was performed. For this study, six female rats were housed with two male rats for 8 days. The pregnant rats were assigned into two groups (n=3 each): control group and dexamethasone group. The dexamethasone received 0.2 mg.kg-1.day-1 water-soluble dexamethasone dose daily diluted in the drinking water from day 14-19 of pregnancy. In the 20th day of gestation, rats were sacrificed and the fetuses were obtained by cesarean derivation. The weight of each fetus was recorded and then were euthanized and the head was fixed in 10% phosphate-buffered formalin. Selected samples were evaluated by light microscopy, and the following measurements were recorded: the perimeter of mandibular bone, Meckel's cartilage and tooth germ; buccolingual length, vertical distance, anteroposterior distance and area of the tooth germ, by the Image J program. There was statistical significance difference with regarding birth weight, mandible perimeter, tooth germ vertical distance and buccolingual distance; area of dental germ and germ perimeter were lower in the dexamethasone versus control. There was no statistical significance difference on Meckel's cartilage perimeter and anteroposterior distance of tooth germ between groups. In conclusion, prenatal exposure to excess dexamethasone impairs mandibular bone and tooth development.