Engineering a TMJ Disc Danielle Lewis Louisiana Tech

Engineering a TMJ Disc Danielle Lewis Louisiana Tech University REU, University of Louisiana at Lafayette Dr. David Mills Louisiana Tech University

What is a TMJ Disc? Temporomandibul ar Joint Disc Ø Located between the base of the skull and the lower jaw Ø Allows for smooth opening and closing of the jaw Ø

TMDs: Temporomandibular Disorders Ø Improper disc placement hampers proper jaw movement, called disc displacements Ø 7 -28% of adult population affected, mainly females between 18 and 25 Ø No known treatment for disorder Ø In severe cases discs are completely removed and patients can no longer move jaw

http: //www. jawjointpainrelief. com/what_is_TMJ. asp

Current Obstacles in Engineering a TMJ disc Recreating the intricate cellular structure Ø 3 regions: anterior band, intermediate zone, and posterior band Ø Anterior and posterior bands: interlaced collagen fiber bundles Ø Intermediate zone: aligned collagen fibers along with tiny fibrochondrocytes and small elastin fibers Ø

Approach of the Mills Lab: Electrospun Scaffolds Ø Electrospinning: l l l A high voltage is passed through a polymer solution inducing an electrostatic repulsion force The polymer is pumped through an insulin syringe, the repulsion force results in the formation of a thin jet This jet is directed toward a grounded collection plate, the solvent evaporates before hitting the collection plate and results in the formation of a polymer scaffold

My Research Plan Culture bovine fibrochondrocytes (FBCs) in 3 different gel environments – agarose, collagen, alginate Ø Treat cells with growth factors to observe their effect on proliferation, cell survival and protein expression Ø l l l Ø b. FGF TGF alpha and beta CTGF Characterize the extracellular matrix being produced by the FBCs

Cell Isolations Ø Bovine FBCs were isolated from TMJ discs taken from cow skulls Ø Cells used in experiments were passage 6, slightly old but still exhibited the characteristic FBC shape

Gels: Collagen and Agarose Ø FBCs were suspended in both collagen and agarose gels and allowed to grow for several days, 18 day group and 8 day group

Fixing, Dehydration, and Paraffin Imbedding Ø Gels fixed in 2% paraformaldehyde Ø Gels were dehydrated by exposing them to a variety of ethanol solutions then infiltrated with pariffin to preserve them indefinitely Ø Gels were then imbedded in a paraffin block in preparation for creating slides Ø Next… Immunohistochemistry

Results Ø Simple examination under phase contrast showed that FBCs thrived better in collagen gels, cells attached and displayed characteristic shape

Is there any explanation for this observation? Ø Expected result Ø Collagen type I abundant in TMJ disc

Conclusions Ø Bovine fibrochondrocytes appeared to prefer the collagen gel environment over the agarose gel environment

Next Steps…. Ø Begin staining gels for extra-cellular matrix proteins l Hypothesis: FBCs grown in collagen gels will exhibit an increase in extra-cellular matrix proteins over those grown in agarose gels Use this experiment as a control and continue by adding growth factors to FBCs in gel culture Ø Compare the amounts and types of extra-cellular matrix proteins found in gels, both with growth factors and without, to that found in actual disc and FBCs grown on electrospun scaffolds Ø

Thank you… Ø Dr. Mills, Kanthi, Skylar, Deepak, Stephanie, Paul Ø Dr. Jones Ø Louisiana Tech for lab facilities in Carson Taylor and the BME building Ø National Science Foundation