FIG. 6.

Histopathologic characteristics of the injured tendons at 60 DPI. (A–I) 60 DPI. (A–C) and (G–I): transverse sections. (D–F) longitudinal sections. (A) ICT. (B) ITTC. (C) injured treated tendon with collagen-polydioxanon implant (ITTC-PDS). At 60 DPI, the newly regenerated tissue filled the defect area of the ICT, was amorphous in nature and several vascularity (Arrow) with poor organization of the collagen fibers and cell alignment were evident in the histologic field. This tissue had low density of the collagen fibers and there was no evidence regarding formation of the new tendon. Unlike ICT (A) the new tendon was formed in the defect area of the ITTC (B) and some collagen remnant (Arrow) were observable through the new tendon however the majority of the defect area was belonged to the new tendon not the collagen remnant. The proportion of the collagen remnants were lower in the ITTC-PDSs (C) as compared with the ITTC and the remnants of the PDS were present around the new tendon. The new tendon was formed though this PDS sheath. (D): at 60 DPI, the collagen fibers and the cells were oriented randomly. The arrows show the cellular and fiber directions. Note that more than two major direction could be seen in the histologic section (D) The cells are immature mainly consisted of lymphocytes and immature tenoblasts (D) At this stage the cellular structures of the ITTC (E) and ITTC-PDS (F) laid in only one direction (arrows show the direction) and the density of the collagen fibers are higher and the cells are more mature, mainly consisted of mature tenoblasts and tenocytes as compared with the ICT (D) At 60 DPI, the gastroc-soleus muscle of the ICT was atrophied and the fibrous connective tissue filled the free spaces between the atrophied muscle fibers (G) The ITTC (H) and ITTC-PDS (I) showed less muscle atrophy and fibrosis compared to the ICT. The muscle fibers are indicated by arrows (G-I) Color staining: hematoxylin and eosin. Color images available online at www.liebertpub.com/tea