Figure 1.

Histology of TMJ in mice post sham surgery and partial discectomy. There were no significant differences between the discectomy and sham mice at 2 weeks post surgery. However, at 4 weeks post discectomy, increased Safranine O staining for proteoglycans was seen throughout the entire articular cartilage of the condyle and in the articular cartilage of the fossa. At 8 weeks post discectomy, chondrocyte clusters appeared (see insert and arrow) and slight reduction of Safranine O staining in the fossa of the temporal bone and the superfacial layer of the condyles was observed. At 12 weeks, fibrillation was observed (see insert and arrow) in the discectomy mice. At 16 weeks, a dramatic overall reduction of Safranine O staining and the loss of articular cartilage (see insert and arrow) were also observed in the discectomy mice. No significant morphologic changes were observed in the subchondral plate and joint margins in the sham surgery or discectomy mice. (Bar=50 µm)