Table 3 Summary of histological results of hetero- and orthotopic cartilage construct implantations

Implant resorption

Not observed

Complete resorption of the submucosal component by week 12

Marginal resorption of cartilaginous ring followed by its fractures at week 16

Immune cell infiltration

Singular leukocytes in the laser-formed wells in immunocompetent mice at weeks 4 and 8 (this reaction was weaker in other groups)

Moderate leukocyte infiltration at weeks 4 and 8

Significant foreign body reaction since week 12

Peri-implant capsule

Thin dense connective tissue capsule formed 8 weeks after the implantation in all study groups (it was rich with fibroblasts)

Thick and loose peri-implant tissue without strict orientation of collagen fibers (the tissue was rich with fibroblasts and blood vessels)

Vascularization

Moderate angiogenesis in the peri-implant capsule in immunocompetent mice at week 8

Number of blood vessels was lower in immunosuppressed mice and sparse in immunocompromised mice at all time points

Intensive growth of new blood vessels at weeks 4 and 8