Effects of Vascular Endothelial Growth Factor (VEGF) on the Progression of Osteoarthritis in the Mouse Temporomandibular Joint

Osteoarthritis (OA) is a chronic degenerative joint disease with a multifactorial etiology including inflammatory mediators. The effects of vascular endothelial growth factor (VEGF) on OA have been studied widely in the field of orthopedics. This study aimed to evaluate whether VEGF could affect the progression of OA in the mouse temporomandibular joint (TMJ). C57BL/6J mice (n = 54) were assigned to three groups, namely, the VEGF+Discectomy, Discectomy, and Sham groups. OA was induced with a discectomy performed on the TMJ in 12-week-old mice in the VEGF+Discectomy and Discectomy groups. Mice in the VEGF+Discectomy group underwent intra-articular VEGF administration after discectomy. For the mice of the Sham group, the joint space was opened surgically, but the disc was not removed. At 4, 8, and 16 weeks after the induction of TMJ OA, the animals were sacrificed. Condylar dimensions and cartilage thickness were measured. Histological changes of the cartilage were assessed using a modified Mankin scoring system. The VEGF+Discectomy group showed a marked reduction of cartilage thickness at 16 weeks post-surgery. According to the modified Mankin scoring system, the VEGF+Discectomy group exhibited the highest scores for the severe reduction of safranin O staining, hypocellularity, and clefts in deep cartilage zones at 16 weeks post-surgery. In the surgically induced TMJ OA mouse model, the VEGF+Discectomy group exhibited highly progressive OA changes in articular cartilage. The detrimental effects of VEGF on TMJ OA may be via its role in the promotion of degradation.