Early Phase of Type 1 Diabetes Decreases the Responsiveness of C-Fiber Nociceptors in the Temporomandibular Joint of Rats

This study established an experimental model that evaluate the effect of type 1 diabetes on nociceptive challenges in the temporomandibular joint (TMJ). Streptozotocin-induced type 1 (STZ 75 mg/Kg) diabetes inhibit the responsiveness of C-fibers nociceptors located in the TMJ of Wistar rats since 7th day after the disease induction. Diabetes-induced hyporesponsiveness of C-fibers nociceptors was associated with significantly reduction of protein level of neuropeptides Substance P and Calcitonin Gene Related Peptide. Diabetic animals pre-treated with Protein Kinase C (PKC)-α and -β inhibitor (GO6976) or PKC- β inhibitor (LY333531) significantly increased capsaicin-induced nociception in the TMJ higher protein levels of Na+/K+-ATPase pump in the trigeminal ganglia. On the other hand, although diabetes inhibits formalin-induced nociception it was observed a higher protein levels of pro-inflammatory cytokine IL1-β and chemokine CINC-1/CXCL-1. Overall, the results of the present work suggest that diabetes causes a hyporesponsiveness of C-fiber and a potentialization of the inflammatory response which may result in the degenerative process of periarticular tissues without pain perception.
Source: Neuroscience - Category: Neuroscience Source Type: research