[Effects of glimepiride on proliferation, differentiation and mineralization of rat mandibular osteoblasts in hyperglycemia].

ABSTRACT

PURPOSE: To evaluate the effects of hyperglycemia and glimepiride on proliferation, differentiation and mineralization of rat mandibular osteoblasts to verify the hypothesis of dental implant administration. METHODS: Primary osteoblasts were isolated and cultured. Then the cells were placed in an osteogenic medium, containing 2 different concentrations of glucose (5.5 mmol/L and 16.5 mmol/L), with or without glimepiride (10 µmol/L). Cell proliferation was evaluated through MTT assay. Alkaline phosphatase (ALP) activity was determined by biochemistric method. Col I protein levels were determined by Western blot. OCN mRNA levels were tested by RT-PCR. SPSS 13.0 software package was used for statistical analysis. RESULTS: Hyperglycemic conditions interfered with the proliferation, ALP activity and OCN mRNA expression of rat osteoblasts, but improved the expression of Col I on day 14. Glimepiride stimulated rat osteoblast proliferation, ALP activity and OCN mRNA expression. The addition of glimepiride to normoglycemic (5.5 mmol/L) cultures registered a significant increase of Col I expression at 7 d and 14 d. Glimepiride significantly increased Col I expression in cells cultured with 16.5 mmol/L glucose for 7 days, but failed to increase at 14 d. CONCLUSIONS: Hyperglycemic conditions interfered with the proliferation, differentiation and mineralization of osteoblasts in rats; however, glimepiride improved the proliferation, differentiation and mineralization of osteoblasts in rats.