Comparison of MMP-9 Expression in Osteoclasts Obtained by Different Methods

Objective To investigate the differences of protein and mRNA expression of matrix metalloproteinase 9(MMP-9) in osteoclasts(OC) and osteoclast-like cells(OLC) obtained by mechanical and inducement methods.Methods Mechanical separation method was used to separate mature osteoclasts from long bones of SD rats aged one-day;and inducement culture method was applied to induce OLC by using RANKL(100 ng/mL) and M-CSF(100 ng/mL).The protein expression of MMP-9 was measured by immunocytochemistry and mRNA expression of MMP-9 was assayed by in situ hybridization.Results The integral optical density(IOD) and average optical density(AOD) of positive cells in the visual field were higher in the 12-d group of inducement method as compared with the 3 d-group of mechanical method.Conclusions It is suggested that the protein and mRNA expression of MMP-9 in OLC obtained by 12 d inducement method is much high than in OC obtained by 3 d mechanical method.OLC obtained by inducement method can be applied in the study of osteoporosis.