Comparison of the biological behaviors of palatal mesenchymal and epithelial cells induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in vitro.

Abstract 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) effectively induces cleft palate at increased doses, but its mechanism of involvement is unclear, and arguments have examined palatal shelf contact and/or fusion failure. The role of different types of cells constituting palatal skulls remains elusive regarding TCDD dosage. No reports have simultaneously compared the biological behaviors of TCDD-induced mesenchymal and epithelial cells in vitro. This study employed primary epithelial and mesenchymal cells as models in vitro to explore proliferation, migration, apoptosis and epithelial-to-mesenchymal transition with two different doses of TCDD (10 nmol/L, 100 nmol/L), contrasted with a control group without TCDD. Interestingly, we found the EMT process of primary palatal epithelial cells occurred automatically in vitro without helping bilateral palatal contact. The results showed that, with the low dose of TCDD, transformation of epithelial cells to mesenchymal cells was inhibited, and mesenchymal cell proliferation and migration were promoted. At high doses, mesenchymal cells decreased, preventing palate development, uprising and contact, while the EMT of epithelial cells decreased more. Regardless of dose of TCDD had no impact on the migration and apoptosis of epithelial cells while increasing the apoptosis of mesenchymal cells according to dose. These findings reveal a potential mechanism of TCDD inducing cleft palate.