RÉSUMÉ
Objective:To study the influence of all-trans retinoic acid (atRA)on craniomaxillofacial development of C57 mice. Methods:Pregnant C57BL mice were divided into 4 groups(n =5)at gestation day (GD)1 0.Mice in three atRA-induction groups were given atRA of 60,80 and 1 00 mg/kg,respectively.The mice in control group were given the equivalent volume of corn oil.All pregnant mice were sacrificed at GD1 9 and the embryos were collected.Stereo microscope was used to observe the craniomaxillofacial morphology.Standardized radiographs were taken and cephalometric analysis was performed.Results:The embryonic body length and body mass of control group surpassed those of 80 and 1 00 mg/kg atRA groups(P <0.05,P <0.01 ).atRA induced craniomaxillofacial malformations and maldevelopment.The mice induced by atRA exhibited a shorter mandibular body and more retrusive position of max-illary and mandibular(∠NAK and ∠NBD)when compared with their norm(P <0.01 ).Significant decrease in craniofacial length (Op-Rh)was observed in all atRA-induced groups(P <0.01 ).Decreases in cranial vault height(Fp-Os)and cranial vault length(Pa-Na)dimensions were observed in 80 and 1 00 mg/kg atRA groups(P <0.05,P <0.01 ).Conclusion:Exogenous atRA dose-depend-ently induces retardation of craniomaxillofacial morphology in embryo of C57BL mice by inhibition of the sagital and vertical dimension development of the bone.