This paper describes the effects of vibration stimulation on chondrocytes in three-dimensional culture in relation to the production of regenerative cartilage tissue, using collagen artificial skin as a carrier and supplementation with hyaluronic acid (used in the conservative treatment of osteoarthritis), and the mechanism of the adaptive response of chondrocytes to mechanical loading. The experimental condition imitates an environment of articular cartilage in vivo that chondrocytes are completely surrounded by the extracellular matrix and receives mechanical stimulation for the weight-bearing mechanics. Chondrocytes were isolated from articular cartilage of porcine metatarsophalangeal joints. Experiments were performed under four different culture conditions: control condition, in which chondrocytes were cultured with atelocollagen gel and collagen artificial skins, and no vibration (HA−Vib−); HA−Vib+, in which chondrocytes were cultured in atelocollagen gel and collagen artificial skins with vibration treatment for 2 weeks; HA+Vib−, in which chondrocytes were cultured in medium containing 0.1% hyaluronic acid; and HA+Vib+, in which chondrocytes were cultured in medium containing 0.1% hyaluronic acid with vibration treatment for 2 weeks. Histologic analysis was conducted at 14 days of culture. The proliferation of chondrocytes was obtained by counting the number of cells with a hemocytometer after 3, 7, 10, and 14 days of culture. The expression of Sox 9 and β-catenin was detected by western blotting analysis. Sox 9 has been reported of involvement in transcription of type IX collagen that binds cartilage-specific type II collagen fibrils. β-catenin plays an important role of signaling pathways of cell proliferation although the relationship between β-catenin and mechanical vibration stimulation has not been clarified yet. The obtained results are as follows. The mechanical vibration enhanced the thickness of extracellular matrix of chondrocytes in histologic section at 14 days of culture and increased the expression of Sox 9. In addition, the mechanical vibration significantly increased the number of chondrocytes after 10 days of culture and promoted the expression of β-catenin. These results show that mechanical vibration promotes the matrix production and proliferation of chondrocytes and that a part of important signaling pathways in relation to mechanical vibration stimulation and proliferation of chondrocytes has been revealed.
Three‐dimensional biomimetic hyaluronic acid hydrogels to investigate glioblastoma stem cell behaviors
