Influence of hormone replacement and of anti-inflammatory on morphologic parameters, histochemical, and immunohistochemical in rats with or without induced TMD

Abstract

The physiological mechanism of temporomandibular joint disorders (TMD) and the ethical issues of studies using human beings, result in difficulty to understand TMD causes'. The TMD are associated with inflammation/pain, which includes biological and behavioral issues. The prevalence, severity and duration of pain of TMD are higher on females, affecting mainly women during reproductive years. Some authors have suggested that ovarian hormones (estrogens) could have a significant role in the TMD’s etiology. The pharmacological approach regarding the treatment of chronic or acute TMD includes analgesics, both steroidal and non-steroidal (NSAID) anti-inflammatory drugs, tricycle anti-depressants and anti-convulsive drugs to treat neuropathic pain. The NSAIDs are indicated by many researchers as first choice drugs and the glicosamins has been used in degenerative processes (osteoarthritis). The aim of the present study is to evaluate in vivo the morphological, histochemical and immunohistochemical aspects of the effect of estrogens (17beta-dietilestylbestrol), parecoxibe, dexamethasone and glicosamine on temporomandibular joint of ovariectomized rat females and castrate rat male. The animals will be previously divided into two groups: with or wihtout induced TMD. 144 male rats and 144 female rats will be distributed into 48 groups (6 animals each) considering the presence or absence of malocclusion; treatment or not with anti-inflammatory drugs or glicosamine; castration and; hormonal replacement. The induction of malocclusion will be acquired be retrusive displacement of mandibular condyle by using a device made with orthodontic bands on superior incisives. After 7 days, the animals will be submitted to the proposed treatments. After 7 days of the treatment, the TMJ of both sides will be removed. One sample will be fixed, decalcified and submitted to histological routines (HE, alcian blue and sirius red). The contralateral TMJ will be macerate, centrifuged and the supernatant will be submitted to immunoassay (ELISA) in order to evaluate pro-inflammatory citocines (IL1-alfa, IL1-beta, IL-6 and TNF-beta). The reading will be performed by spectrophotometry (wave length = 450nm). (AU)