Effect of γ-ray irradiated poly(L-lactide) on the differentiation of mouse osteoblast-like MC3T3-E1 cells

The purpose of this study was to clarify the effects of gamma-ray irradiated poly(L-lactide) (PLLA) on the proliferation and differentiation of mouse osteoblast-like MC3T3-E1 cells. The PLLA was gamma-irradiated at the dose of 10, 25 or 50 kGy, and the molecular weight of irradiated PLLA decreased with increasing it-radiation dose, The proliferation and differentiation of MC3T3-E1 cells cultured on irradiated PLLA for 2 weeks were evaluated using micromass culture. The gamma-irradiation of PLLA did not affect the proliferation, but stimulated the differentiation of MC3T3-E1 cells cultured on irradiated PLLA. These results suggested that lower change in the molecular weight of PLLA was responsible for stimulation of the differentiation of MC3T3-E1 cells cultured on irradiated PLLA. Furthermore, the proliferation and calcification of MC3T3-E1 cells cultured in the medium containing low molecular weight PLLA for 2 weeks were evaluated. The low molecular weight PLLA also stimulated the calcification of MC3T3-E1 cells with no effect on the proliferation, The gamma-irradiation was suitable for PLLA on the differentiation of mouse osteoblasts.