Influence of estrogen cycle on temporomandibular joint synovial membrane in rat with deviated mandible.
Temporomandibular disorders (TMD) are known to be more prevalent and severe in women than in men, especially in those who are in their reproductive age. In those patients reproductive hormones may play a vital role in the host adaptive capacity of the temporomandibular joint (TMJ). In order to clarify the relationship between TMD prevalence and estrogen cycle, a mandible deviated animal model was carried out, and the expression of inducible nitric oxide synthase (iNOS), an essential enzyme in the pathogenesis of inflammatory arthritis, was investigated in the rat's synovial tissue. An appliance was attached to the rat's incisors to produce a lateral deviation of the mandible during the metestrus phase, and the animals were sacrificed in the proestrus and estrus phase, when the estrogen was at the highest and lowest level, respectively. Immunostaining was then performed for 2 consecutive estrous cycles to demonstrate iNOS expression in the synovial membrane of the TMJ. The immunoreactivity for iNOS was more intense in the synovial membrane on the contralateral side in the proestrus phase (estrogen peak phase). These observations suggest that iNOS expression in the synovial membrane with mandibular deviation may be exacerbated in the presence of estrogen.
Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. giokorts@tmd.ac.jp
Giovanna
G
Kishimoto
Jun
J
Hosomichi
Takeshi
T
Muramoto
Zuisei
Z
Kanno
Kunimichi
K
Soma
D000818:Animals; D004967:Estrogens / Q000502:physiology*; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D007124:Immunoenzyme Techniques; D008310:Malocclusion / Q000150:complications*; D052247:Nitric Oxide Synthase Type II / Q000032:analysis / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D013583:Synovial Membrane / Q000201:enzymology*; D013704:Temporomandibular Joint / Q000201:enzymology; D013705:Temporomandibular Joint Disorders / Q000201:enzymology / Q000209:etiology / Q000503:physiopathology*
D004967:Estrogens; D052247:Nitric Oxide Synthase Type II