Acta Academiae Medicinae Sinica

Acta Academiae Medicinae Sinica

Acta Academiae Medicinae Sinica ›› 2012, Vol. 34 ›› Issue (3): 207-211.doi: 10.3881/j.issn.1000-503X.2012.03.003

• Original Articles • Previous Articles     Next Articles

Effect of Fluid Flow-induced Shear Stress on Osteoclast Formation Induced by Osteocyte

CUI Liang, LI Xiao-tong, ZHANG Ding   

  1. Department of Stomatology, PUMC Hospital, CAMS and PUMC, Beijing 100730, China
  • Received:2011-07-21 Revised:2012-06-30 Online:2012-06-29 Published:2012-06-29
  • Supported by:

    Supported by the National Natural Sciences Foundation of China(31070829,81041010)

Abstract: Objective To study the role of osteocyte in bone remodeling due to mechanical loading in vitro. Methods MLO-Y4 osteocyte-like cells were exposed to fluid flow-induced shear stress(12dyn/cm2)for 0, 1, 2, 4, 6, 12, and 24 hours. Osteocyte exposed to shear stress at different time points were used in co-culture system for 9 days, and then the cells were stained with tartrate-resiseant acid phosphatase on the 9th day and the amount of positively stained osteoclasts were counted and compared. The expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa (RANKL) were detected by semi-quantitative reverse transcription polymerase chain reaction (semi-quantitative RT-PCR). Results Compared with bone cells without stimulation with fluid flow-induced shear stress, the amount of osteocytes significantly decreased at all time points after the application of fluid flow-induced shear stress (all P<0.05). The OPG expression at mRNA levels was significantly up-regulated in the first 12 hours (P<0.001), the RANKL mRNA expression was significantly down-regulated in the first 4 hours (P<0.05), and the RANKL/OPG ratio significantly decreased within 12 hours (P<0.01). However, all these indicators showed no significant difference at 24 hours when compared with the pre-stimulation level. Conclusion Osteocytes may act as mechanosensors that are able to inhibit bone resorption after mechanical loading; however, such effect shows certain adaptation ability to shear stress as time goes.

Key words: MLO-Y4 cells, fluid shear stress, osteoclast

CLC Number: