Formation of Gap Junctions and Expression of Connexin 43 in Cultured Malassez’s Epithelial Rest Cells

Background and Aim: The purpose of this study was to investigate the formation of gap junctions and to characterize the expression of Connexin (CX) 43 during the proliferation of Malassez’s epithelial rest (MER) cells. Materials and Methods: MER cells derived from the porcine periodontal ligament were cultured in 35 mm dishes as 2D culture. MER cells mixed with type 1 collagen gels were also cultured as 3D culture. The 2D culture cells were classified into 3 groups; group 1 was the single cell stage, group 2 was the cell to cell contact stage, and group 3 was the multiple cell contact stage. All the cells were observed using immunofluorescence and immuno-electron microscopy with a CX43 antibody. RTPCR and quantitative RT-PCR were also used to analyze CX43 mRNA levels. Results: CX43-positive cells were not observed in group 1. A few CX43-positive spots were observed on the cell membranes between cells in group 2 and many CX43-positive spots were observed on the cell membranes in group 3. A few immunogold particles were observed between cell membranes. CX43 expression of group 3 had the highest mRNA levels. In the 3D culture, no CX43-positive spots were observed at any of the attached areas, and the expression of CX43 mRNA in cells of the 3D culture were much lower than in the 2D culture. Conclusion: These results suggest that the 2D culture is better than the 3D culture to investigate epithelial cell morphology and that CX43 expression is important for MER cells to proliferate.