β-Defensin-4 (HBD-4) is expressed in chondrocytes derived from normal and osteoarthritic cartilage encapsulated in PEGDA scaffold

Defensins are antibiotic peptides involved in host defense mechanisms, wound healing and tissue repair. Furthermore, they seem to play an important role in protection mechanisms in articular joints. The aim of this study was to investigate β-defensin-4 expression in chondrocytes taken from articular cartilage of knees of patients with osteoarthritis (OA) compared to normal cartilage, in vivo in explanted tissue, and in vitro in chondrocytes encapsulated in construct PEGDA hydrogels. The present investigation was conducted to try and elucidate the possible use of β-defensin-4 as a relevant marker for the eventual use of successive scaffold allografts, and to provide new insights for hydrogel PEGDA scaffold efficacy in re-differentiation or repair of OA chondrocytes in vitro. Articular cartilage specimens from OA cartilage and normal cartilage were assessed by histology, histochemistry, immunohistochemistry and Western blot analysis. The results showed strong β-defensin-4 immunoexpression in explanted tissue from OA cartilage and weak β-defensin-4 expression in control cartilage. The chondrocytes from OA cartilage after 4 weeks of culture in PEGDA hydrogels showed the formation of new hyaline cartilage and a decreased expression of β-defensin-4 immunostaining comparable to that of control cartilage. Our results suggest the possibility of applying autologous cell transplantation in conjunction with scaffold materials for repair of cartilage lesions in patients with OA using β-defensin-4 as a relevant marker.