Mechanical loading increased BMP-2 expression which promoted osteogenic differentiation of tendon-derived stem cells

Authors

  • Yun Feng Rui,

    1. Faculty of Medicine, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China
    2. The Hong Kong Jockey Club Sports Medicine and Health Sciences Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
    3. Department of Orthopaedic Surgery, Shanghai 9th People's Hospital, School of Medicine, Shanghai, Jiaotong University, Shanghai, China
    Search for more papers by this author
  • Pauline Po Yee Lui,

    Corresponding author
    1. Faculty of Medicine, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China
    2. The Hong Kong Jockey Club Sports Medicine and Health Sciences Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
    3. Program of Stem Cell and Regeneration, School of Biomedical Science, The Chinese University of Hong Kong, Hong Kong SAR, China
    • Faculty of Medicine, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China. T: 852-2632-3072; F: 852-2646-3020.
    Search for more papers by this author
  • Ming Ni,

    1. Faculty of Medicine, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China
    2. The Hong Kong Jockey Club Sports Medicine and Health Sciences Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
    3. The Department of Orthopaedics, The General Hospital of Chinese PLA, Beijing 10085, China
    Search for more papers by this author
  • Lai Shan Chan,

    1. Faculty of Medicine, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China
    2. The Hong Kong Jockey Club Sports Medicine and Health Sciences Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
    Search for more papers by this author
  • Yuk Wa Lee,

    1. Faculty of Medicine, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China
    2. The Hong Kong Jockey Club Sports Medicine and Health Sciences Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
    Search for more papers by this author
  • Kai Ming Chan

    1. Faculty of Medicine, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China
    2. The Hong Kong Jockey Club Sports Medicine and Health Sciences Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
    Search for more papers by this author

  • YF Rui and PPY Lui have contributed equally to this article.

Abstract

This study aimed to investigate the effect of repetitive tensile loading on the expression of BMP-2 and the effect of BMP-2 on the osteogenic differentiation of tendon-derived stem cells (TDSCs) in vitro. Repetitive stretching was applied to TDSCs isolated from rat patellar tendon at 0%, 4%, and 8%, 0.5 Hz. The expression of BMP-2 was detected by Western blotting and qPCR. To study the osteogenic effects of BMP-2 on TDSCs, BMP-2 was added to the TDSC monolayer for the detection of ALP activity and calcium nodule formation in a separate experiment. TDSCs adhered, proliferated, and aligned along the direction of externally applied tensile force while they were randomly oriented in the control group. Western blotting showed increased expression of BMP-2 in 4% and 8% stretching groups but not in the control group. Up-regulation of BMP-2 mRNA was also observed in the 4% stretching group. BMP-2 increased the osteogenic differentiation of TDSCs as indicated by higher ALP cytochemical staining, ALP activity, and calcium nodule formation. Repetitive tensile loading increased the expression of BMP-2 and addition of BMP-2 enhanced osteogenic differentiation of TDSCs. Activation of BMP-2 expression in TDSCs during tendon overuse might provide a possible explanation of ectopic calcification in calcifying tendinopathy. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:390–396, 2011

Ancillary