Biomedical Research

Cell-to-cell interactions play important roles in regulating cell proliferation and differentiation, tissue production, organ construction and ontogenesis. The purpose of this study was to investigate the effects of oral epithelial (OE) cells on osteoblasts’ behavior for proliferation and osteogenic differentiation. Osteoblast-like cells were co-cultured in 6-well-dishes with or without OE cells growing on cell culture inserts. After 1, 3, 7 and 14 d, the characteristics of osteoblast-like cells were evaluated regarding cell proliferation, mRNA expression levels of collagen type I, RUNX2 and bone Gla protein (BGP), and alkaline phosphate (ALP) activity. In cell proliferation assays, the numbers of osteoblast-like cells cultured with or without OE cells increased over time for 2 w, but the proliferation of osteoblast-like cells co-cultured with OE cells plateaued after 7 d. The mRNA expression levels of type I collagen in osteoblast-like cells cultured with or without OE cells tended to decrease over time, but the decrease in osteoblast-like cells co-cultured with OE cells was more dramatic. The mRNA expression levels of RUNX2 and BGP in osteoblast-like cells cultured without OE cells tended to increase over time, but those increases in cells cultured without OE cells were more dramatic than in osteoblast-like cells cocultured with OE cells. The ALP activity of osteoblast-like cells cultured without OE cells increased until 7 d and then decreased at 14 d, but osteoblast-like cells cultured with OE cells underwent little change in ALP activity throughout the 14 d of culture. The ALP activity of osteoblast-like cells cultured without OE cells was significantly higher at 7 and 14 d than in osteoblast-like cells cultured with OE cells. In conclusion, these results indicate that OE cells inhibit the osteogenic differentiation and function of osteoblast-like cells.

Author(s): Kenichi Matsuzaka, Tadashi Horikawa, Eitoyo Kokubu, Takashi Inoue
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