First immunohistochemical evidence of human tendon repair following stem cell injection: A case report and review of literature

Figure 2 Histological and immunohistochemical analysis of representative sections from the first part of the biopsy that was investigated in this study. A and B: Section stained with Azan trichrome stain; cells are in red and collagen is in blue (inset in Panel A, position of the high-power photomicrograph displayed in Panel B; white arrows in Panel B, elongated, fibroblast-like cells (tenocytes) arranged in long and parallel chains between collagen fibers); C-G: Immunohistochemical detection of type I collagen in a section adjacent to the one shown in Panel A; counterstaining was performed with Mayer's hematoxylin (black arrow in Panel C, region with almost complete absence of immunolabeling for type I collagen but a high cell density; insets in Panel C, position of the high-power photomicrographs displayed in Panels D-G, showing the following four different regions: D: Immunolabeling for organized, slightly undulating type I collagen (black arrows in Panel D) and high cell density; E: Immunolabeling for organized type I collagen with discernible crimp arrangement (white arrow in Panel E) and a few cells (yellow arrows in Panel E); F: Immunolabeling for organized type I collagen with discernible crimp arrangement (white arrow in Panel F) and absence of cells; G: Absence of immunolabeling for type I collagen and a few, rounded cells (black arrows in Panel G); H and I: Immunohistochemical detection of aggrecan in a section adjacent to the ones shown in Panels A and C of the same biopsy; counterstaining was performed with Mayer's hematoxylin (inset in Panel H, position of the high-power photomicrograph displayed in Panel I; black arrows in Panel I, immunolabeling for aggrecan); J and K: Immunohistochemical detection of type II collagen in another section adjacent to the ones shown in Panels A, C and H of the same biopsy; counterstaining was also performed with Mayer's hematoxylin (inset in Panel J, position of the high-power photomicrograph displayed in Panel K).