Abstract: ObjectiveTo explore the effect of transforming growth factor-β3(TGF-β3)on palatal cleft in C57BL/6J mice induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD).MethodsOn gestation day 10(GD 10),the pregnant mice were randomly divided into two groups:the treated group(with TCDD exposure at the dose of 64μg/kg body weight)and the control group(with corn oil of 16 ml/kg body weight).The embryos were examined under stereomicroscope to detect the incidence of cleft palate on GD 18.5 and the palatal shelves were dissected from the embryos for RNA and protein extractions on GD 13.5,GD 14.5,and GD 15.5.The expression of TGF-β3 mRNA and protein were detected with reverse transcription-PCR(RT-PCR)and western blot.ResultsThe incidence of cleft palate was 100% in TCDD group(39/39) and there was no cleft palate observed in the control group(0/42).The expression of TGF-β3 mRNA and protein were gradually up-regulated in TCDD group on different phases of the development of palatal shelves(P<0.05).ConclusionTCDD can induce a stable formation of cleft palate and the up-regulation of the TGF-β3 expression and the over expression of TGF-β3 may be a key signal pathw ay resulting in TCDD-induced cleft palate.