The Effects Of Fluid Shear Stress On Proliferation And IGF-1Expression Of Rat’s Condylar Subchondral Bone Osteoblast

[Objective] To observe the changes of proliferation and insulin growth factor-1(IGF-1) expression of primary rat’s condylar subchondral bone osteoblast stimulated by fluid shear stress in vitro,so that to make a primary understanding of the relationship between the expression of IGF-1and cell proliferation during the process of shear stress induced remodeling of condylar subchondral bone.[Methods] The experiment is subchondral bone which obtains by the surgery in rat’s condylar is a material.cultured with modified repeating enzymatic digestion-adherent explants method and high suger DMEM,uses the inverted microscope observation cell growth.confimred by obsevration under microscope, osteoblasts were subjected to fluid shear stress with the "shaking" Zhou proposed loading system at different strain for30min(uses the fourth generation of osteoblasts and let the cells arrange to4groups by different volume of DMEM:control group、1.5ml group、2ml、3ml group,observe the shape and arrangement of the cells in each group,and cell cycle were evaluated using flow eytometry, and the expression of IGF-1was detected by ELISA.To set control groups, stress-free cells were also cultured in the same conditions and tested on different time points accroding to the experiment groups.[Results]①sufficient osteoelasts obtained by modified repeating enzymatic digestion-adherent explants method and meet the typical morphological and biological characteristics of osteoblasts.②after fluid shear stress for30min,had significantly improved the activity of cell proliferation (P<0.05),but1.5ml and2ml group (P> 0.05).③1.5ml、2ml、3ml group higher than control gruop and3ml highest (P<0.05),but1.5ml、2ml、control gruop was no significant difference (P>0.05).[Conclusions] In the experimental, modified repeating enzymatic digestion-adherent explants method and high suger DMEM can culture and obtain purified neonatal SDrat’s Subchondral bone osteoblasts, the cell may take mechanics function the material.lt was found that the shear stress of3ml DMEM (0.35dyne/cm2), when exerted on the osteoblasts for30min, had significantly improved the activity of cell proliferation and the expression of IGF-1, that must be the certain intensity of fluid shear stress can obviously affect the primary rat’s condylar subchondral bone osteoblast’s metabolism, proliferation activities,causes its synthesis IGF-1,promote the formation of new bone and cartilage bone remodelling.