RESUMEN
<p><b>OBJECTIVE</b>To establish a good animal model of cleft palate and confirm whether 2, 3, 7, 8-tetrachloro-p-dibenzodioxin (TCDD) and Dexamethasone (DEX) induced palatal cleft in mice is related to the fold change of transforming growth factor-beta 3 (TGF-beta3) and activin receptor-like kinase 5 (Alk5).</p><p><b>METHODS</b>Pregnant mice were treated with oral medication of TCDD and intraperitoneal injection with DEX on GD10-12 in experimental group while the control group without any treatment. Then embryos were examined on GD17.5 under stereomicroscope for calculating the incidence of cleft palate and palatal shelves were dissected from the staged embryos respectively for RNA extraction on GD13.5, GD14.5 and GD15.5. At last the real-time PCR and SYBR Green I detection were used for RNA relative quantification.</p><p><b>RESULTS</b>Cleft palate could be induced 100% in C57BL/6J fetal mice with TCDD and DEX, thus established a stable animal model for further molecular studies of cleft palate. There were no significant difference in expression level of TGF-beta3 and Alk5 on GD13.5 among the groups, but the differences were statistically significant on GD14.5 and GD15.5 (P < 0.05). On the contrary, the expression level of Alk5 were significantly higher in experimental group (P < 0.05).</p><p><b>CONCLUSION</b>Combined effects of TCDD and DEX could induce a stable formation of cleft palate and down-regulated mRNA of TGF-beta3 and up-regulated Alk5 may contribute to the occurrence of cleft palate.</p>