Ultrastructural findings: A) Injured tendon of a 28 DPI rabbit. The small sized collagen fibrils are not differentiated and are unimodally distributed. B) Injured tendon of an 84 DPI rabbit. The collagen fibrils diameters are larger than those of the 28 DPI rabbits and show a bimodal distribution. However, they are much smaller than those of the normal contralateral tendons. C) Normal contra lateral tendon: The collagen fibrils show a multimodal distribution pattern and collagen fibrils of different sizes are seen in this section (Scale bar = 360 nm).