Figure 3.

Collagen Type I expression in stromal cells in the OS TME in xenografts and in clinical biopsies from canine patients. Trichromic staining (left) of spontaneous canine OS (A) or mouse subcutaneous xenografts of 143B+ADMSC (B) were included in paraffin and sliced. The same field shown with trichromic staining was also assessed for fiber orientation using polarized light (right). Type I collagen is positively birefringent with respect to the length of the fibers and appears with blue and purple staining in the trichromic and polarized light images, respectively. Higher magnifications of the dashed squares are shown in panels 1 and 2. In 3, the merge of 1 and 2 is shown. Scale bar 100 μm. Lower panels show immunohistochemistry staining for Ki67 (left panel) and collagen Type I (right panel). Nuclei were counterstained with hematoxylin. Arrows indicate positive staining.