This study aims to investigate spatial and temporal changes in cadherin-11 (CAD-11) expression and their effects on cartilage degeneration in the temporomandibular joint (TMJ) of guinea pigs with spontaneous osteoarthritis (OA).
Dunkin-Hartley (DH) and Bristol strain 2 (BS2) guinea pigs at ages of 1, 3, 6, 9, and 12 months were categorized into two groups and analyzed. The bilateral TMJ condyles of DH and BS2 guinea pigs were harvested and fixed. The distribution and expression profiles of CAD-11, collagen type II, and matrix metalloproteinase 3 (MMP-3) were detected by immunohistological assays. Histological micrographs of the condyle cartilage were obtained and analyzed.
Osteoarthritis can be spontaneously induced by mechanical stress in DH guinea pigs. The main histopathological changes in the TMJ structure and increased expression of MMP-3 occurred within 6-9 months of ages in DH guinea pigs with spontaneous OA. By contrast, minimal to mild cartilage degradations were observed in the TMJ of BS2 guinea pigs even at the age of 12 months. From as early as 3 months of age, the expression levels of CAD-11 were upregulated in the TMJ of DH guinea pigs compared with those in BS2 animals. CAD-11 expression differed between the two groups at 12 months of age.
Increased CAD-11 expression within cartilage is associated with the development and progression of OA between the two strains of guinea pigs. Therefore, CAD-11 expression in TMJ could be an important predisposing factor for the development of spontaneous OA.