Fig. 4

pHA-TDSC-Exos scaffold promoted the repair of tendon defects in the rat model. A The rat model of tendon defect was treated with pHA-TDSC-Exos scaffold. B Gross view of injured tendons treated with pHA or pHA-TDSC-Exos at 2, 4 and 8 weeks after surgery. C H&E staining of wound sections treated with pHA or pHA-TDSC-Exos at 2, 4 and 8 weeks after surgery. N: normal area; W: wound area. Scale bar: 200 μm (× 100); 100 μm (× 200). D Histological scores of tendons at 8 weeks after surgery (Bars: mean ± SE; n = 6; one-way ANOVA with Tukey’s multiple comparison test, *p < 0.05 and **p < 0.01). E Masson’s trichrome staining of wound sections treated with pHA or pHA-TDSC-Exos at 2, 4 and 8 weeks after surgery. N: normal area; W: wound area. Scale bar: 200 μm. F Immunohistochemistry of type III collagen during the process of tendon repair. Scale bar: 100 μm. G The ultimate stress of regenerated tissues treated with pHA or pHA-TDSC-Exos at 8 weeks after surgery (Bars: mean ± SE; n = 6; one-way ANOVA with Tukey’s multiple comparison test, *p < 0.05 and **p < 0.01); H The elastic modulus of regenerated tissues treated with pHA or pHA-TDSC-Exos at 8 weeks after surgery (Bars: mean ± SE; n = 6; one-way ANOVA with Tukey’s multiple comparison test, *p < 0.05 and **p < 0.01)