Cell Type and Distribution in the Porcine Temporomandibular Joint Disc

Detamore, Michael S.; Hegde, Jay N.; Wagle, Rohan R.; Almarza, Alejandro J.; Montufar-Solis, Dina; Duke, P. Jackie; Athanasiou, Kyriacos A.

doi:10.1016/j.joms.2005.10.009

« Previous Next »Journal of Oral and Maxillofacial Surgery
Volume 64, Issue 2 , Pages 243-248, February 2006

Cell Type and Distribution in the Porcine Temporomandibular Joint Disc

Michael S. Detamore, PhD
- Assistant Professor, Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS
- Address correspondence and reprint requests to Dr Detamore: 4132 Learned Hall, 1530 West 15th St, University of Kansas, Lawrence, KS 66045-7609
Jay N. Hegde, BS
- Medical Student, University of Texas Southwestern Medical School, Dallas, TX
Rohan R. Wagle, BA
- Medical Student, Baylor College of Medicine, Houston, TX
Alejandro J. Almarza, PhD
- Postdoctoral Fellow, Musculoskeletal Research Center, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA
Dina Montufar-Solis, BS
- Senior Research Associate, Department of Diagnostic Sciences, University of Texas Health Science Center Dental School, Houston, TX
P. Jackie Duke, PhD
- Professor, Department of Orthodontics, University of Texas Health Science Center Dental School, Houston, TX
Kyriacos A. Athanasiou, PhD, PE
- Professor, Department of Bioengineering, Rice University, Houston, TX; and Adjunct Professor, Department of Oral & Maxillofacial Surgery, University of Texas Health Science Center Dental School, Houston, TX

Purpose

Surprisingly little is known about the cellular composition of the temporomandibular joint (TMJ) disc, which is a crucial piece of the puzzle in tissue engineering efforts. Toward this end, cell types were identified and quantified regionally in the TMJ disc.

Materials and Methods

Porcine TMJ discs were examined by histology, electron microscopy, and immunohistochemistry. Histology consisted of hematoxylin and eosin staining to identify regional variation of cell type and cell numbers. Transmission electron microscopy was used to elucidate differences in organelle content and pericellular matrix between TMJ disc cells and chondrocytes from hyaline cartilage. Immunohistochemistry was used to assess the presence of smooth and skeletal muscle character in the TMJ disc.

Results

The overall ratio of fibroblasts to chondrocyte-like cells in the TMJ disc was approximately 2.35 to 1, with the highest relative number of chondrocyte-like cells in the intermediate zone. Electron microscopy revealed distinct differences between TMJ disc chondrocyte-like cells and chondrocytes from hyaline cartilage with respect to organelles and the pericellular region. Immunostaining identified smooth muscle in the form of vessels, which were most prominent in the anterior band. Skeletal muscle was not observed.

Conclusion

The cells of the TMJ disc are distinctly different from cells of hyaline cartilage, and consequently should not be referred to as chondrocytes. TMJ disc cells are comprised of heterogeneously distributed subpopulations, with fibroblasts predominating over fibrochondrocytes.