Ion Currents Mediated by TRPA1 Channels in Freshly Dissociated Rat Articular Chondrocytes: Biophysical Properties and...

Background: Articular chondrocytes are specialized cells in synovial joint cartilage, responsible for maintaining and regenerating the extracellular matrix. Inflammation disrupts the balance between matrix synthesis and degradation, leading to cartilage breakdown. This process, commonly observed in conditions such as osteoarthritis, results in chondrocyte dysfunction and accelerates joint degeneration. Since TRPA1 channels are implicated in inflammatory processes, this study investigates the expression of TRPA1 channels in freshly dissociated rat articular chondrocytes and their modulation by anti-inflammatory agents. Methods: We used the whole-cell patch-clamp method to assess TRPA1 channel expression and modulation. Results: Freshly dissociated chondrocytes exhibit ion currents attributable to TRPA1 channel expression, with higher magnitudes observed in medium-sized cells. These currents decrease over time in primary culture. Treatment with pro-inflammatory agents (IL-1α, IL-1β, and LPS) increases TRPA1's current magnitude. IL-1β treatment directly induces transient TRPA1 currents. Several signaling components activated during inflammation contribute to the IL-1β-induced enhancement of TRPA1 current density, including IL-1 R1, the adaptor protein MyD88, and the downstream kinases IRAK1 and IRAK4. Conclusions: Our findings demonstrate that healthy rat chondrocytes express functional TRPA1 channels and that inflammatory processes modulate their expression.