Estrogenic effect on swelling and monocytic receptor expression in an arthritic temporomandibular joint model

17- -Estradiol Enhanced Allodynia of Inflammatory Temporomandibular Joint through Upregulation of Hippocampal TRPV1 in Ovariectomized Rats

“…Our results also showed that food intake decreased with the decreased head withdrawal threshold after induction of TMJ inflammation, further supporting that food intake can be a proper indicator for TMJ inflammation/pain. However, our result was contrary to a previous report in which the 24 h food intake was increased in the ovariectomized rats with estradiol replacement, compared with that in the rats ovariectomized without estradiol replacement after induction of TMJ inflammation (Guan et al, 2005). This discrepancy could be caused by a different means of meal pattern analysis.…”

“…Despite the controversy, we showed here that estradiol could exacerbate mechanical allodynia of inflamed TMJ in the ovariectomized rats, suggesting that rats with a higher level of plasma estradiol would be more sensitive to mechanical stimuli over the inflamed TMJ. It has been previously shown that estradiol enhanced visually assessed swelling around the inflamed TMJ (Guan et al, 2005), implying that the TMJ with greater swelling could be more sensitive to mechanical stimuli because of higher pressure in the local tissue than the one with less swelling. Considering that estradiol can modulate the functions of both nervous and immune systems, it is difficult to differentiate whether our observation that estradiol exacerbation of inflamed TMJ pain was caused by estradiol-enhanced inflammation in the TMJ or by estradiol-enhanced sensitization in the nervous system of pain processing, or by both.…”

Sustained Inflammation Induces Degeneration of the Temporomandibular Joint

“…The increased collagen content may be accounted for by the increased cellularity and is likely a hypertrophic response (Abubaker et al, 1996;Okazaki et al, 1996). CFA has been injected into the superior joint compartment in the present and other studies (Harper et al, 2001;Guan et al, 2005;Spears et al, 2005;Flake et al, 2006). In the present study, we observed few phenotypic changes in condylar cartilage.…”

“…CFA is a solution of antigen emulsified in mineral oil and consists of inactivated and dried mycobacteria. CFA injection is simple and reproducibly induces TMJ inflammation, as shown in previous work by us and sustained Inflammation Induces Degeneration of the temporomandibular Joint others with a focus on the acute phase of inflammation (Harper et al, 2001;Guan et al, 2005;Spears et al, 2005;Flake et al, 2006;Lai et al, 2006;Wu et al, 2010;Kou et al, 2011). However, single-dose CFA injections in previous work were primarily associated with transient inflammatory changes in the TMJ.…”

“…1A). Previous work has utilized only single CFA injections (Harper et al, 2001;Guan et al, 2005;Spears et al, 2005;Flake et al, 2006;Lai et al, 2006). Rats in the control group received saline injections (same volume).…”