Scientific Articles   |    
Up-Regulation of Bone Morphogenetic Proteins in Cultured Murine Bone Cells with Use of Specific Electric Fields
Zhenyu Wang, MD, PhD1; Charles C. Clark, PhD1; Carl T. Brighton, MD, PhD1
1 Department of Orthopaedic Surgery, University of Pennsylvania School of Medicine, 424 Stemmler Hall, Philadelphia, PA 19104-6081. E-mail address for C.T. Brighton: ctb@mail.med.upenn.edu
View Disclosures and Other Information
Note: The authors thank Dr. Paul Billings for his help with the BMP-2 enzyme-linked immunosorbent assay.
The authors did not receive grants or outside funding in support of their research for or preparation of this manuscript. One or more of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity (royalties from Biolectron, Inc., to perform the research). No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Investigation performed at the McKay Laboratory of Orthopaedic Surgery Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania

The Journal of Bone and Joint Surgery, Incorporated
J Bone Joint Surg Am, 2006 May 01;88(5):1053-1065. doi: 10.2106/JBJS.E.00443
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case


Background: Capacitively coupled electric stimulation has been successfully used in the treatment of bone nonunions and to effect spinal fusions. However, the pathway of biologic events whereby this is accomplished has not been fully elucidated. To determine whether bone morphogenetic proteins (BMPs) could be involved, the effect of electrical stimulation on BMP gene expression was investigated.

Methods: Postconfluent cultures of MC3T3-E1 bone cells were exposed to a series of capacitively coupled signals in which the duration, amplitude, frequency, and duty cycle were sequentially and systematically varied. The cellular response was measured by quantifying the mRNA levels of BMP-2 through BMP-8, as well as the BMP antagonists gremlin and noggin, with use of reverse transcription followed by real-time quantitative polymerase chain reaction. BMP-2 protein was measured by enzyme-linked immunosorbent assay, and alkaline phosphatase activity was measured by a specific colorimetric assay.

Results: The results showed that BMP-2 through BMP-8, gremlin, and noggin were all normally expressed by MC3T3-E1 cells, and could be significantly up-regulated by specific and selective capacitively coupled electric fields (p < 0.05). However, mRNA expression for BMP-2, 4, 5, 6, and 7 was consistently up-regulated several times higher than that for BMP-3 and BMP-8, gremlin, and noggin under identical conditions. Concomitantly, BMP-2 protein production and alkaline phosphatase activity were both significantly increased in the same electrically stimulated cultures (p = 0.001 and p < 0.01, respectively).

Conclusions: These data clearly show that our optimal capacitively coupled signal (60 kHz, 20 mV/cm at a 50% duty cycle for twenty-four hours) can specifically, selectively, and simultaneously up-regulate the expression of a number of osteoinductive BMPs; other BMPs and antagonists are only moderately affected.

Clinical Relevance: Electrical stimulation may be a useful treatment modality for in vivo situations where bone induction is required, since it is noninvasive, safe, effective, can be easily targeted to a variety of anatomic sites, can provide a controlled production of BMPs, and can be used repeatedly. The optimal duration (continuous stimulation at 100% duty cycle) and frequency (60 kHz) determined in this in vitro study are the same—and the amplitude (20 mV/cm) is in the same range (12 mV/cm)—as are used clinically.

Figures in this Article
    Sign In to Your Personal ProfileSign In To Access Full Content
    Not a Subscriber?
    Get online access for 30 days for $35
    New to JBJS?
    Sign up for a full subscription to both the print and online editions
    Register for a FREE limited account to get full access to all CME activities, to comment on public articles, or to sign up for alerts.
    Register for a FREE limited account to get full access to all CME activities
    Have a subscription to the print edition?
    Current subscribers to The Journal of Bone & Joint Surgery in either the print or quarterly DVD formats receive free online access to JBJS.org.
    Forgot your password?
    Enter your username and email address. We'll send you a reminder to the email address on record.

    Forgot your username or need assistance? Please contact customer service at subs@jbjs.org. If your access is provided
    by your institution, please contact you librarian or administrator for username and password information. Institutional
    administrators, to reset your institution's master username or password, please contact subs@jbjs.org


    Accreditation Statement
    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
    CME Activities Associated with This Article
    Submit a Comment
    Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
    Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

    * = Required Field
    (if multiple authors, separate names by comma)
    Example: John Doe

    Related Content
    The Journal of Bone & Joint Surgery
    JBJS Case Connector
    Topic Collections
    Related Audio and Videos
    PubMed Articles
    Clinical Trials
    Readers of This Also Read...
    JBJS Jobs
    Oklahoma - The University of Oklahoma
    S. Carolina - Department of Orthopaedic Surgery Medical Univerity of South Carlonina
    Pennsylvania - Penn State Milton S. Hershey Medical Center
    Louisiana - Ochsner Health System