Expression dynamics of WNT5a, β-Catenin, and COL-I in developing periodontium and the undifferentiated DF. The differences of expression patterns of WNT5a, β-Catenin and COL-I between developing periodontium (Dev. Periodontium) and the DF beneath AF (undifferentiated DF) were studied. The boxed regions of Dev. Periodontium were magnified in A', C', E', and the boxed region of DF beneath AF was magnified in A'', C'', E''. Dark blue arrows point to the mature periodontium; light blue arrows point to the developing periodontium; green arrows point to the undifferentiated DF; red arrows point to the apical papilla. (A-A'', B) WNT5a expression pattern showed the gradually increasing expression levels from the undifferentiated DF to the matured periodontal ligaments. The expression level in Dev. Periodontium was stronger than that in the DF beneath AF (n=4, P<0.05). (C-C'', D) β-Catenin pattern showed the expression level in DF was higher than that in the periodontium. The expression level in Dev. Periodontium was stronger than that in the DF beneath AF (n=3, P<0.05). (E-E'', F) Col-I pattern showed the expression level in the DF was higher than that in the periodontium. The expression level in Dev. Periodontium was stronger than that in the DF beneath AF (n=3, P<0.05). Scale bars represent 100μm (A-A'', C-C'', E-E'').