Chitosan-Collagen 3D Matrix Mimics Trabecular Bone and Regulates RANKL-Mediated Paracrine Cues of Differentiated Osteoblast and Mesenchymal Stem Cells for Bone Marrow Macrophage-Derived Osteoclastogenesis.

Recent studies have identified the regulatory mechanism of collagen in bone ossification and resorption. Due to its excellent bio-mimicry property, collagen is used for the treatment of several bone and joint disease such as arthritis, osteoporosis, and osteopenia. In bone, the biological action of collagen is highly influenced by the interactions of other bone materials such as glycosaminoglycan and minerals. In view of the above perceptions, collagen was crosslinked with chitosan, hydroxyapatite (H), and chondroitin sulfate (Cs), to produce a natural bone-like 3D structure and to evaluate its effect on bone homeostasis using bone marrow mesenchymal stem cells, osteoblast, and bone marrow macrophages. The XRD and micro-CT data confirmed the arrangement of H crystallites in the chitosan-collagen-H-Cs (CCHCs) three-dimensional (3D)-matrix and the three-dimensional structure of the matrix. The stimulatory osteoblastogenic and exploitive osteoclastogenic activity of 3D-matrices were identified using differentiated osteoblasts and osteoclasts, respectively. Besides, osteogenic progenitor's paracrine cues for osteoclastogenesis showed that the differentiated osteoblast secreted higher levels of RANKL to support osteoclastogenesis, and the effect was downregulated by the CCHCs 3D-matrix. From that, it was hypothesized that the morphology of the CCHCs 3D-matrix resembles trabecular bone, which enhances bone growth, limits bone resorption, and could be a novel biomaterial for bone tissue engineering.