Expression of growth factors in the early phase of supraspinatus tendon healing in rabbits

Growth factors are known to appear during wound healing. We hypothesized that growth factors would also appear during the healing process of a rotator cuff tear. We determined the expression of various growth factors during healing of acute rotator cuff tears in the rabbit. We made a full-thickness defect in the supraspinatus tendon of 27 Japanese white rabbits. The shoulders were harvested on days 1, 3, 5, 7, 9, 11, 14, 2 1, and 28 postoperatively (n = 3 at each time point). We assessed the expression of basic fibroblast growth factor, insulin-like growth factor 1, platelet-derived growth factor, and transforming growth factor p. Basic fibroblast growth factor appeared with its peak on days 7 and 9, insulin-like growth factor I appeared with its peak on day 5, platelet-derived growth factor appeared with a mild expression between days 7 and 14, and transforming growth factor p appeared with constant mild expression throughout the observation period. It is likely that each of these growth factors plays a role in the early phase of healing of the supraspinatus tendon in rabbits.