The expression of MMP-13/TIMP-1affected by mechanical strain under inflammatory environment in MC3T3-E1

Objective To investigate the gene and protein expression of MMP-13 and TIMP-1induced by mechanical strain in inflammatory environment in MC3T3-E1. Methods Monocyte-macrophage cells(RAW264.7) from mouse were stimulated by pgLPS( 100 ng/ml) for 24 hours,then the supernatant was collected.Osteoblast of mouse(MC3T3-E1) was stimulated by 20％ concentration of supernatant for 24 hours,the mechanical strain(cyclic compressive forces via a four-point bending system) was used for 0 (control),1,3,6 hours,the gene and protein expression of MMP- 13/TIMP- 1were detected through real time PCR(RT-PCR) and Immunohistochemistry,respectively.Results Compared with the controls,the gene and protein expression of MMP-13 and TIMP-1was obviously increased,and has positive correlation with time after stimulated by mechanical strain in MC3T3-E1in inflammatory environment,the difference was significant (P ＜ 0.05).Conclusions The current results indicated that mechanical strain will significantly affect the expression of MMP-13 and TIMP-1in inflammatory environment,The results suggested that external force in inflammatory environment may affect ECM metabolism depending on the functional role of MMP-13 and TIMP-1. Key words: Li popolysaccharide;  Mechanical strain;  Osteoblasts;  Matrix metalloproteinase-13; Tissue inibitors of metalloproteinase-1