Abstract: PURPOSE: To study the mechanism by which retinoic acid (RA) can cause mouse cleft palate and folic acid could antagonize the effect of RA. METHODS: Pregnant mice were given excess dose of RA to induce cleft palate, and then their embryonic palatal mesenchymal (EPM) cells were extracted by the method of incomplete digestion and cultured at gestation days 14, 17 (GD14, 17). After being identified, the cells were treated with different concentration of folic acid and then their proliferation was tested by MTT method. SPSS 16.0 software package was used for data analysis. RESULTS: ① Giving pregnant mice 50 mg/kg RA at GD10, 12 could cause mice cleft palate; ② The purity of EPM cells treated by incompleted digestion reached 98%; ③The proliferation of EPM cells of GD14 was inhibited by RA, but folic acid at the concentration of 20 μg/mL, 40 μg/mL could antagonize the effect of RA. CONCLUSIONS: ①Excess dose of RA could cause cleft palate in mouse and an important mechanism is the inhibition of EPM cells’ proliferation; ②Folic acid could antagonize the inhibition effect caused by RA. Supported by Natural Science Foundation of Department of Science and Technology of Shanxi Province (201311056-5).

Key words: Folic acid, Retinoic acid, Cleft palate, Embryonic palatal mesenchymal cells