DYNAMICS OF SERUM TNF-Α IN EXPERIMENTAL CARRAGEENAN-INDUCED INFLAMMATION OF THE TEMPOROMANDIBULAR JOIN

Abstract

The temporomandibular joint (TMJ) is a complex anatomical structure highly susceptible to inflammatory processes due to its dual functional load and intricate innervation. Inflammatory lesions of the TMJ are associated with pain, impaired function, and may lead to systemic changes. A key pathogenetic factor in inflammation is tumor necrosis factor-alpha (TNF-α), which plays a critical role in initiating and sustaining the pro-inflammatory response. Currently, there is a lack of comprehensive studies examining the dynamics of TNF-α in blood serum under conditions of induced inflammation specifically in the TMJ region.Several studies have confirmed the involvement of TNF-α in inflammatory processes in various tissues, including dental pulp, periapical lesions, and joints. TNF-α stimulates the secretion of other pro-inflammatory cytokines, activates immune system cells, and promotes bone tissue resorption. Carrageenan is a reliable agent for modeling the acute phase of inflammation in experimental animals. However, there is insufficient research investigating changes in TNF-α levels specifically in carrageenan- induced TMJ inflammation.The aim of the study is to investigate the dynamics of TNF-α concentration in the blood serum of rats under conditions of experimental carrageenan-induced TMJ inflammation.Materials and Methods. The experiment was conducted on 36 WAG rats, with carrageenan or saline injected into the TMJ region. The animals were divided into 6 groups, with blood samples collected at 3 hours, and on days 1, 3, 7, and 15. TNF-α levels in serum were determined using enzyme-linked immunosorbent assay (ELISA).Results and Discussion. As early as 3 hours after carrageenan injection, a trend toward increased TNF-α levels was observed, with peak values on day 3 (a 2.55-fold increase compared to the control). From day 7, TNF-α levels began to decrease, nearly reaching control values by day 15. The dynamics of TNF-α levels indicate a classic biphasic inflammatory response. The carrageenan model effectively and reproducibly mimics acute TMJ inflammation and may be valuable for further studies on pathogenesis and evaluation of anti-inflammatory therapy efficacy in dentistry. Conclusions. Intra-articular carrageenan injection into the TMJ induces a pronounced systemic pro-inflammatory response with elevated TNF-α levels in blood serum. The peak TNF-α concentration is observed on day 3, consistent with the active phase of cytokine-mediated inflammation. By day 15, levels approach those of the control, indicating a reduction in inflammatory activity.