Date of Graduation

Fall 2013

Degree

Master of Natural and Applied Science in Biology

Department

Biology

Committee Chair

Brian Weaver

Abstract

Temporomandibular joint disorder (TMJD) along with temporomandibular disorders (TMD) may be the most prevalent pain disorders in the United States, especially among women. Since TMJD affects the trigeminal nerve and has high co-morbidity with migraine headache and sinus headache, it is associated with significant social and economic burdens. The cytokine TNF-α is reported to be elevated in the joint capsule and correlates with pain. The goal of my study was to better understand the cellular mechanisms involved in mediating the nociceptive effects of TNF-α on trigeminal ganglia neurons that provide sensory innervation to the TMJ. Male Sprague-Dawley rats were injected bilaterally with TNF-α and changes in nocifensive responses to mechanical stimulation and cytokine levels in trigeminal ganglia were determined by protein array analysis at 2 and 24 hours post injection. There were eight cytokines that were elevated 2 hours following injection with TNF-α above vehicle control while all eight had returned to the level of vehicle control 24 hours following injection. This temporal cellular response correlated positively with behavioral nocifensive responses to mechanical stimulation. These eight cytokines are likely to play a key role in the development of pain during TMJD. In conclusion, I have found that elevated levels of TNF-α in the joint capsule promotes sensitization of primary trigeminal nociceptors via a mechanism that temporally correlates with increased levels of cytokines.

Keywords

temporomandibular joint disorder (TMJD), tumor necrosis factor-alpha (TNF-α), cytokines, nocifensive, sensitization

Subject Categories

Biology

Copyright

© Zachary Louis Durham

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