Folic Acid Deficiency and Cleft Palate Appearance in Mice

Introduction: A deficit of dietary folic acid (FA) has been considered an aetiological factor in the appearance of cleft palate (CP) in humans. However, the reasons why this cleft palate is produced have been poorly investigated. Objective: Our aim was to determine the effects of the absence of FA in the palate of the progeny of mouse females under a FA deficient diet. Methods: C57 mouse females received either a control (2 mg FA/kg diet -control group-) or FA deficient (0 mg FA/kg diet + 1% succinyl sulfathiazole -experimental group-) diets for 2, 4, 6, 8, 10, 12, 14 or 16 weeks. Phoetuses (n=39) were extracted at embryonic day 13.5 (E13.5) and their palatal shelves were cultured for 18 or 36 hours. Other phoetuses were extracted at E17 (n=205) and were examined externally to check the presence of CP. Both cultures and heads were embedded in paraffin, sectioned and haematoxilin and eosin stained. 18 hour palatal shelf cultures were TUNEL stained and TUNEL positive cells were counted. In 36 hour cultures, opposing medial edge epithelia (MEE) adhesion and disappearance were measured. E17 mouse heads were microscopically analysed looking for CP. Results: Palate cultures from embryos progeny of 2 week experimental females showed a significant reduction of MEE cell death, palatal shelf adhesion and fusion. Alteration of palatal ossification was observed in phoetuses from 4 week experimental females onwards. Partial or complete CP was observed in 4% of the whole experimental group phoetuses, starting in the progeny from 2 week FA deficient diet mouse females. Conclusion: Even acting during a short time, FA deficiency alters palate development, affecting both the medial edge epithelium and the mesenchyme.

This work has been supported by grants FIS (PI06/0184) and UCM-CM to the Complutense Research Group 920202, 2006.