Effect of sex and sex hormones on formalin-induced temporomandibular joint inflammation / Influencia do sexo e dos hormonios sexuais na inflamação induzida pela administração de formalina na articulação teporomandibular de ratos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The greater prevalence of pain conditions in temporomandibular joint and inflammatory diseases in female suggests the involvement of sex hormones in temporomandibular joint pain and inflammation. Previous studies suggest that the high estradiol level during the rat estrous cycle and the administration of estradiol or progesterone in ovariectomized female or testosterone in orchiectomized male rats decrease formalin-induced temporomandibular joint nociception. The mechanism by which sex hormones decrease temporomandibular joint nociception is unknown, however could be mediated by decreasing temporomandibular joint inflammation. For that reason, the aim of this study was to evaluate the effect of sex and sex hormones on formalin-induced temporomandibular joint inflammation. To measure temporomandibular joint inflammation, we evaluated plasma extravasation and neutrophil migration. Formalin induced significant lower temporomandibular joint plasma extravasation and neutrophil migration in proestrus females than in males and in diestrus females. Formalin-induced temporomandibular joint plasma extravasation and neutrophil migration in ovariectomized females were similar to those of sham-operated diestrus females and significantly higher than those of sham-operated proestrus females. Estradiol but not progesterone administration in ovariectomized females significantly reduced formalin-induced temporomandibular joint plasma extravasation and neutrophil migration. Formalin-induced temporomandibular joint plasma extravasation and neutrophil migration were not affected by orchiectomy, while testosterone administration in orchiectomized males significantly decreased them. Taken together, these findings demonstrate a pronounced anti-inflammatory effect of estradiol and testosterone in temporomandibular joint and suggest that this effect may mediate, at least in part, the antinociceptive effect of these hormones on the temporomandibular joint.

ASSUNTO(S)

progesterone sexual dimorphism estradiol dimorfismo sexual progesterona

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