Figure 6

Blocking of transforming growth factor-β (TGF-β)-induced synovial fibrosis in osteoarthritits (OA). STR/ort mice (4 weeks old) were injected intra-articularly with Ad-TGF-β combined with Ad-Smad7 or Ad-luciferase (Ad-luc) and injected again 2 weeks later. Two weeks after the last injection, knee joints were isolated for histology and synovial fibrosis was assessed. Synovial thickness was determined by measuring the width of the synovium opposite the growth plates in the femur. (a) Synovial thickness had increased significantly after adenoviral TGF-β overexpression (p < 0.005). More than 50% of this increase in width was prevented by simultaneous expression of Smad7 (p < 0.005). The number of procollagen type I-expressing cells (b) had increased as well after exposure to TGF-β (p < 0.0005). This was also inhibited by more than 50% by co-expression of Smad7. Histological representations of the measurements give an indication of actual thickness (c) and procollagen positive cells (d) Error bars display standard error.