Collagen fibril morphometry in transected rat extensor tendons.

The regenerative potential of completely transected tendon has been assessed in rat extensor tendon. Collagen fibril diameter distributions were calculated within the gap region of the healing tissue at 10, 30, 60, 120 and 240 days postoperatively. At each age the distribution was found to be unimodal with no indication of any return of bimodality. These results suggest that mechanical stimuli may be a controlling factor in determining fibril diameters and that mature tendon may be unable to reproduce a bimodal collagen fibril diameter distribution subsequent to trauma.