Participation of peripheral tachykinin NK₁ receptors in the carrageenan‐induced inflammation of the rat temporomandibular joint

Abstract

Temporomandibular disorders represent one of the major challenges in dentistry therapeutics. This study was undertaken to evaluate the time course of carrageenan-induced inflammation in the rat temporomandibular joint (TMJ) and to investigate the role of tachykinin NK(1) receptors. Inflammation was induced by a single intra-articular (i.art.) injection of carrageenan into the left TMJ (control group received sterile saline). Inflammatory parameters such as plasma extravasation, leukocyte influx and mechanical allodynia (measured as the head-withdrawal force threshold) and TNFalpha and IL-1beta concentrations were measured in the TMJ lavages at selected time-points. The carrageenan-induced responses were also evaluated after treatment with the NK(1) receptor antagonist SR140333. The i.art. injection of carrageenan into the TMJ caused a time-dependent plasma extravasation associated with mechanical allodynia, and a marked neutrophil accumulation between 4 and 24h. Treatment with SR140333 substantially inhibited the increase in plasma extravasation and leukocyte influx at 4 and 24h, as well as the production of TNFalpha and IL-1beta into the joint cavity, but failed to affect changes in head-withdrawal threshold. The results obtained from the present TMJ-arthritis model provide, for the first time, information regarding the time course of this experimental inflammatory process. In addition, our data show that peripheral NK(1) receptors mediate the production of both TNFalpha and IL-1beta in the TMJ as well as some of the inflammatory signs, such as plasma extravasation and leukocyte influx, but not the nociceptive component.

Sustained Inflammation Induces Degeneration of the Temporomandibular Joint

“…Surgical disruption to physiological structures, including bite raise, severance of the bilaminar zone, or induced condyle hypermobility, leads to inflammatory changes and subchondral bone degeneration in the TMJ (Mao et al, 1998;Sharawy et al, 2003;Yamaza et al, 2003;Embree et al, 2011). TMJ inflammation can also result from injection of chemical irritants, including carrageenan (Denadai-Souza et al, 2009), ovalbumin (Habu et al, 2002), and complete Freund's adjuvant (CFA) (Kerins et al, 2004;Wu et al, 2010;Kou et al, 2011). CFA is a solution of antigen emulsified in mineral oil and consists of inactivated and dried mycobacteria.…”

Peripheral Neurokinin-1 Receptors Contribute to Kaolin-Induced Acute Monoarthritis in Rats

“…In rodent models of arthritis induced by complete Freund's adjuvant or CGN, substance P is a potent mediator of increased microvascular permeability and leukocyte influx via activation of NK 1 receptors located on postcapillary endothelial cells [8,17,39]. However, the allodynia seen in CGN-induced temporomandibular joint arthritis was not affected by the blockade of NK 1 receptors [17], so the role of peripheral substance P in joint pain is less clear.…”

“…Synovial lavage fluid samples (20 µl) were thawed, and MPO activity was measured as an index of migration of activated polymorphonuclear (PMN) cells to the joint, as previously described [15,16,17]. For this purpose, samples were incubated with tetramethylbenzidine (1.6 m M ), NaPO 4 (80 m M ) and hydrogen peroxide (H 2 O 2 ; 0.3 m M ), and absorbance was read at 650 nm.…”

“…Our previous studies show that intra-articular injection of CGN alone causes knee inflammation and secondary tactile allodynia by triggering a wide inflammatory cascade, including increased NO production and protein oxidation, that may maintain an ongoing state of inflammation in the joint [15,16]. CGN injection into the rat temporomandibular joint induces a marked time-dependent plasma extravasation associated with neutrophil accumulation and increased IL-1β levels [17]. These findings indicate that CGN, independently of kaolin, is able to produce inflammation and pain-related processes in the joint.…”

Tramadol effects on clinical variables and the mechanical nociceptive threshold in horses

“…One method, von Frey fi laments, described by Maximilian von Frey in 1896, has been used with relative safety and repeatability for the evaluation of cutaneous sensitivity in horses (REDUA et al, 2002;OLESKOVICZ et al, 2006) and dogs (DUQUE et al, 2004, KUKANICH & PAPICH, 2011. As an alternative to the von Frey fi laments, electronic methods have been developed and tested on other species (CUNHA et al, 2004;DENADAI-SOUZA et al, 2009) and showed advantages over the classic method, including a reduction in the number of attempts required to evaluate the nociceptive threshold, the elimination of problems in the standardization of the fi laments.…”