Localization of CD44 and hyaluronan in the synovial membrane of the rat temporomandibular joint

Authors

  • Akiko Suzuki,

    Corresponding author
    1. Division of Oral Anatomy, Department of Oral Biological Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
    • Division of Oral Anatomy Department of Oral Biological Science Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Niigata 951-8514, Japan
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    • Fax: 81-25-223-6499

  • Kayoko Nozawa-Inoue,

    1. Division of Oral Anatomy, Department of Oral Biological Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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  • Norio Amizuka,

    1. Division of Oral Anatomy, Department of Oral Biological Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
    2. Center for Transdisciplinary Research, Niigata University, Niigata, Japan
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  • Kazuhiro Ono,

    1. Division of Dental Hygiene and Health Promotion, Faculty of Dentistry, Niigata University, Niigata, Japan
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  • Takeyasu Maeda

    1. Division of Oral Anatomy, Department of Oral Biological Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
    2. Center for Transdisciplinary Research, Niigata University, Niigata, Japan
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Abstract

Previous studies have pointed out a lack of adhesion structures in the synovial lining layer of the rat temporomandibular joint (TMJ) despite showing an epithelial arrangement. CD44, a major cell adhesion molecule, plays crucial roles as an anchor between cells and extracellular matrices by binding hyaluronan (HA) for the development of organs or the metastasis of tumors. The present study examined the localization of CD44 in the synovial membrane of the rat TMJ by immunocytochemistry for OX50, ED1, and Hsp25, which are markers for the rat CD44, macrophage-like type A, and fibroblast-like type B synoviocytes, respectively. Histochemistry for HA-binding protein (HABP) was also employed for the detection of HA. OX50 immunoreactions were found along the cell surface and, in particular, accumulated along the surface of the articular cavity. Observations by a double immunostaining and immunoelectron microscopy revealed that all the OX50-immunopositive cells were categorized as fibroblastic type B cells, which had many caveolae and a few vesicles reactive to intense OX50. However, the macrophage-like type A cells did not have any OX50 immunoreaction in the synovial lining layer. A strong HABP reaction was discernable in the extracellular matrix surrounding both OX50-positive and -negative cells in the synovial lining layers, exhibiting a meshwork distribution, but weak in its sublining layer. This localization pattern of CD44 and HABP might be involved in the formation of the epithelial arrangement of the synovial lining layer. Furthermore, OX50 immunonegativity in the type A cells suggests their low phagocytotic activity in the rat TMJ under normal conditions. Anat Rec Part A 288A:646–652, 2006. © 2006 Wiley-Liss, Inc.

Ancillary