Protective effects of ozone therapy on cartilage degeneration in temporomandibular joint osteoarthritis.

Temporomandibular joint osteoarthritis (TMJ-OA) is a condition characterized by progressive cartilage degradation and inflammation, with matrix metalloproteinases (MMPs) playing an important role in these processes. The present study evaluated the effects of ozone therapy on the expression of MMP-2 and MMP-9 and the cartilage preservation in a monosodium iodoacetate (MIA)-induced TMJ-OA rat model. Female Wistar rats were administered a single intra-articular injection of MIA (2 mg/TMJ in 30 µL saline) or saline into the left TMJ. Three days after the MIA injection, rats received two intra-articular injections of an oxygen-ozone mixture (40 µg/mL, 50 µL) administered at a 1-week interval. To perform immunohistochemical analysis, TMJs were collected at days 5 and 12 post-MIA injections (2 days after each injection of the oxygen-ozone mixture) and for histological analysis at days 14 and 21 post-MIA injection. The results suggested that ozone therapy exhibited a protective effect against cartilage degradation on day 14, yet this effect was not observed on day 21 post-MIA injection. Histological evaluation demonstrated partial cartilage preservation, while immunohistochemistry showed that levels of MMP-9 elevated in the condyle by MIA injection were reduced by ozone therapy. Conversely, MMP-2 scores remained unaffected across all experimental groups. The application of ozone therapy did not result in alterations to the type or intensity of the inflammatory infiltrate observed at the degenerative phase of the osteoarthritis. These findings suggest that a brief treatment protocol of ozone therapy, applied during the inflammatory phase, modulates MMP-9 expression and provides transient protection against cartilage degradation in TMJ-OA.