The Influence Of Fluid Shear Stess On Osteoblastic Cells Proliferation Through ERK5Signaling Pathway

[Object] This study explore to the involvement of ERK5signaling pathway in the proliferation response of osteoblastic cells to fluid shear stress, to provide the basis to establish the transmission mechanism of mechanical stress in the bone tissue.[Methods] Fluid shear stress on cultured osteoblastic cells exert the same intensity at different times with EKR5inhibitor, MTT assay and immunofluorescence labeling method to detect proliferative activity of osteoblastic cells, analysis of the ERK5signaling pathway mediated by the fluid shear stress and the proliferation of osteoblasts.[Results] Obvious role of fluid shear stress (12dyn/cm2) for the same strength and the different time, comparative standing in the control group, the fluid shear stress in the short time (t≤lh) to promote the proliferation of osteoblasts (P＜O.05), and the osteoblastic cells growth curve forward, CylinDl and CDK4expression was significantly higher(P<0.05); but1.5h、2h significantly inhibited the proliferation (P＜O.05); the same time FSS role, use BIX02188of ERK5inhibitor inhibited ERK5signaling pathway, the osteoblasts proliferative response was inhibited, and the reduced expression of CylinD1and CDK4, compared with the control group showed significant differences, their expression were positively correlated (r=0.55,P<0.05).[Conclusion] Normal physiological environment, ERK5signaling pathway is involved in the proliferative activity of osteoblasts. The12dyne/cm2FSS stimulus can through the ERK5-CylinDl-CDK4signaling transduction pathway play a positive regulatory role of osteoblasts proliferation activity, the short time (t≤60min) continuous FSS stimulation of ERK5-CylinDl-CDK4in signaling transduction pathway positive regulation of cell cycle and promote the proliferation of osteoblasts; the long time(>60min) FSS stimulation will inhibit phosphorylation of ERK5, then by ERK5-CylinDl-CDK4signaling transduction pathway on cell cycle regulatory factors play a role in inhibiting cell proliferation.