Background Articular cartilage has limited self ‐repair ability due to the lack of blood vessels, lymphatic vessels, and nerves. Constructing cartilage tissue engineering microunits provides adipose‐derived mesenchymal stem cells (ADSCs) with a natural microenvironment conducive to differentiation into chondrocytes and the deposition of chondrocyte extracellular matrix (ECM). Objective This study aims to utilize porous chitosan microspheres (PCMs), which provide a favorable microenvironment for cartilage repair, as a biological scaffold to composite ADSCs inducing a microenvironment for cartilage repair and analyzing the therapeutic effects of PCMs combined with ADSCs on rat knee joint cartilage injury. Methods ADSCs were isolated and cultured from neonatal mice, and the cells were induced and tested. ADSCs were seeded onto PCMs to construct tissue engineering microunits in vitro. The cell compatibility and degradation of PCMs were tested, and the adhesion, proliferation, and growth distribution of ADSCs on PCMs were observed. PKH‐26 was used to label adipose stem cells to investigate their fate during cartilage repair. The constructed tissue engineering microunits were transplanted into a rat model of articular cartilage injury to evaluate the repair effect. Results (1) The isolated and cultured ADSCs showed strong proliferative activity and differentiation ability. (2) CCK‐8 assay and subcutaneous embedding showed that the microspheres had good biocompatibility. (3) PKH‐26–labeled stem cells remained in the cartilage defect area after 2 weeks. (4) Animal experiments showed that the repair effect and mechanical performance in the experimental group were significantly better than those in the control and blank groups, with significantly better gross and histological scores compared to the control group. Conclusion ADSCs isolated and cultured from neonatal mice had high purity, good immunophenotype, and strong proliferative and differentiation abilities. PCMs exhibited good porosity, biocompatibility, and low immunogenicity. The cartilage tissue microunits constructed from PCMs combined with adipose stem cells effectively promoted the repair and regeneration of articular cartilage injury, providing a new approach for the treatment of articular cartilage injury.
Liu et al. (Thu,) studied this question.