Expression of Runx2 in the dental follicle cells of mouse tooth germ at bell stage

SHANG Shu-xian; PAN Ke-qing; LI Yu; CHEN Yan-qing; LI Shu

doi:10.15956/j.cnki.chin.j.conserv.dent.2017.07.001

Abstract：AIM:To study the expression of Runx2 in the dental follicle cells(DFCs) of mouse tooth germ at bell stage.METHODS:Mandibles including the first molar germs were removed from 5~7-day-old BALB/c mice and 5 μm sections were prepared for the following experiments.In situ hybridization and immunohistochemical (ICH) techniques were used to determine the tissue distribution and cellular localization of Runx2 mRNA and protein in dental follicle tissue.Then, loose dental follicle tissue around mandibular first molar germs at bell stage were isolated under stereomicroscope from the mice.Primary DFCs were obtained by trypsin digestion and cultured in vitro.Total RNA and protein were respectively extracted from cultured DFCs.RT-PCR and Western blot were adopted to observe the expression of Runx2 mRNA and protein in DFCs.RESULTS:Mandibular first molar germs of 5~7-day-old BALB/c mice were at later bell stage, the epithelial root sheath had already innerly folded, however, the root still could not be seen.Dental follicle tissue surrounding the developing dental germ was loose fibrous connective tissue.In situ hybridization showed Runx2 mRNA expression in DFCs,but IHC showed no Runx2 protein expression in the cells.RT-PCR showed Runx2 mRNA experssion in DFCs, while Western blot showed no Runx2 protein expression in the cultured DFCs.CONCLUSION:Runx2 may have a role in the development and differentiation of DFCs, but not at dental follicle of pre-root-formation.