Fig. 5: Engrafted iPSC-tenocytes express tendon functional extracellular matrix at two weeks after transplantation.

a Histological analyses of iPSC-tenocytes rats, untreated rats, and uninjured rats at 4 weeks after transplantation. Masson’s trichrome staining shows collagen fiber (blue), cytoplasm (red), and nuclei (purple). Representative pictures of the transplanted area (left Achilles tendon) are shown. The boxed areas in the first and third rows are shown with higher magnification in the second and fourth rows, respectively. Scale bars: 50 μm. b Density of cell fibers stained with eosin. Image J was used for calculation (n = 4: biologically independent samples). Data represent mean ± SE. *P < 0.05, two-tailed Welch’s t-test. c Rose diagrams of the regenerated fiber angle from the horizontal line. The angle of hematoxylin-positive cells was analyzed using Image J, and the average and variance were calculated. d Biodistribution of DiR-labeled iPSC-tenocytes at 24 h and 2 and 4 weeks after transplantation. e Immunohistochemistry of regenerated Achilles tendons harvested from iPSC-tenocytes rats and untreated rats at 2 weeks after transplantation. Tissues were stained with anti-human specific vimentin (red), type I collagen (green), and type III collagen (green) antibodies and co-stained with DAPI (blue). Representative images are shown. Dotted lines indicate non-regenerative regions. Positive rates of anti-human specific vimentin to DAPI were calculated using Image J (n = 4: biologically independent samples). Data represent mean ± SE. Scale bars: 100 μm. Source data are provided as a Source Data file.