Changes in urinary bone resorption markers (pyridinoline, deoxypyridinoline) resulting from experimentally-induced osteoarthritis in the temporomandibular joint of rats.

The purpose of this study was to quantify the urinary bone resorption markers, pyridinoline (Pyr) and deoxypyridinoline (Dpyr), excreted from experimentally-induced osteoarthritis (OA) in the temporomandibular joint (TMJ) of rats. Osteoarthritic lesions were induced by intra-articular injection of collagenase into the right TMJs of 16-week-old male rats. The whole day's urine was collected from each animal one day before the injection and 5, 7, 11 and 14 days after the injection. Urine samples were analyzed by high-perfomance liquid chromatography and fluorescence spectroscopy. Histological changes in condyle were examined by using paraffin sections with toluidine blue staining. Degenerative changes were observed in the articular cartilage of the experimental group on day 7 and day 14 after the injection of collagenase. The concentration of Pyr was remarkably high in the experimental group, and consequently the Pyr to Dpyr ratio was significantly higher (p<0.05) in the experimental group than in the control group from 7-14 days after the injection. These findings suggest that a urinary Pyr/Dpyr ratio would be available for the detection of degenerative changes in condyle relevant to temporomandibular joint osteoarthritis (TMJ OA).