Changes in the innervation of rabbit craniomandibular joint tissues associated with experimental induction of anterior disk displacement: histochemical and immunohistochemical studies.

We have previously reported that surgical induction of anterior disk displacement (ADD) in a rabbit craniomandibular joint (CMJ) leads to histopathological changes consistent with osteoarthritis. This paper reports the changes that were noted in the innervation of rabbit CMJ tissues following surgical induction of ADD. The right joint of 30 rabbits was exposed surgically and the discal attachments were severed except for the posterior discal attachment (bilaminar zone). The disk was then displaced anteriorly and sutured to the zygomatic arch. The left joints was used as sham-operated control. CMJ tissues were then removed after fixation and processed for histochemical localization of nerve fibers using the silver impregnation technique and immunohistochemical localization of neurofilaments using monoclonal antibodies. The results showed an absence of nerve fibers in the control and experimental disks and their presence in the control and experimental bilaminar zones. The bilaminar zone adhesions to the experimental condyles were also innervated. The spread of nerve fibers into the pathological fibrous adhesions surrounding the arthritic condyles in this animal model of ADD may indicate a possible mechanism of nociception in this disease.