Study On Expression Of EGF, Keratin5 On Palate Of Retinoic Acid Induce Cleft Palate Of Mouse

Objective:Cleft lip and/or cleft palate (CL/P) is one of the most common malformations among live births, occurring with an incidence of 1.42‰in the world and 1.82‰in China. CL/P is caused by genetic factors and interaction with environmental factors. It is so complicated that until now little is known about its causation.During the development of the palate shelves, medial edge epithelial (MEE) cells have its own fixed turnover pattern whose change may have the relationship with the development of the cleft palate. In the possess, exogenous teratogen may be an effect of the nomal change of MEE cells that make cleft palate.Retinoic acid (RA) is a kind of drug with distinct teratogenic action. It is belived that excess of the RA may make influence to the change of the MEE cells and restrain the proliferation of embryonic palatal mesenchyme (EPM) Cells induces the cleft palate.Epidermal growth factor (EGF) is one of the cell growth factors, which can make promotion in cell proliferation. Abbott et al confirmed that EGF expressed in the embryonic palatal shelves from GD12 to GD15 and changed in space-time in the MEE and EPM throughout the palatogenesis. The EGF can make MEE cells and EPM cells proliferation in vitro.Keratin5 (K5) isⅡ-type keratinose whose molecular mass is 58KDa. K5 expresses in basal cell of the laminated epithelium. The research make that K5 can special express in epithelium of the palate shelves. There is little report about the role of K5 in the palatogenesis in domestic.The present study is to use the CP model induced by RA, and to observe expression level of EGF and Keratin 5 in palate shelves and then to analyze the effects RA has on them and reach the conclusion of teratogenic mechanism by RA and provide experience for the clinic and experiment.Method:In the experiment,using the well established mouse model of RA-induce cleft palate, we detected the expression and distribution of EGF and Keratin 5 at GD14, GD15 and GD16 in control group and RA treated group by immunohistochemistry.Result:1. The expression of EGF was detectable evenly in the developing MEE cells until the palatal shelves fused following apoptosis happened in the MEE cells. In control group,GD15 ,EGF bengin to descend in MEE. In GD14 and GD16 the expression of EGF in oral epithele is higher than the nasal epithele. In GD15 ,the expression of EGF begin to fall in EPM.2. In RA-treat group ,the expression of EGF in MEE is high in GD15 and be lower in EPM in GD14.3. The expression of K5 was detectable in the developing MEE cells until the palatal shelves fused following apoptosis happened in the MEE cells. In control group, the expression of K5 is high in MEE cells in GD15.4. In RA-treat group,Keratin 5 is higher in epithele than that in control group and did not change in GD14 and GD15.Conclusion:1. EGF was expressed both in epithelial and mesenchymal components during palate development, the data proved that the up-regulation of EGF in GD15 in RA-treated group promote the generation and differention of MEE.2. K5 expresses in epithele during palate development.In control group, K5 is high in MEE in GD15 and did not up-regulated suggested that K5 could be used as a labeling protein for MEE cells beginning to fusing.