Comparative Evaluation of Synovial Multipotent Stem Cells and Meniscal Chondrocytes for Capability of Fibrocartilage Reconstruction

Objective Meniscus tissue is composed of highly aligned type I collagen embedded with cartilaginous matrix. This histological feature endows mechanical properties, such as tensile strength along the direction of the collagen alignment and endurance to compressive load induced by weight bearing. The main objective of this study was to compare the fibrocartilage construction capability of different cell sources in the presence of mechanical stimuli. Design Synovial multipotent stem cells (SvMSCs) and meniscal chondrocytes (MCs) from immature and mature rabbits were maintained under similar conditions for comparative evaluation of growth characteristics and senescence tendency. The differentiation potential of cell sources, including fibrocartilage generation, were comparatively evaluated. To determine the capability of fibrocartilage generation, cultured cell sheets were rolled up to produce cable-form tissue and subjected to chondrogenic induction in the presence or absence of static tension. Results Although SvMSCs showed superior cell growth characteristics during in vitro cell expansion, senescence-associated β-galactosidase expression was consistently higher, compared with MCs. MCs showed glycosaminoglycan (GAG)-rich matrix formation during default in vitro chondrogenesis. While application of static tension significantly reduced GAG production, MCs continued to show robust tissue growth. SvMSCs showed inferior chondrogenic differentiation and diminished tissue growth in the presence of static tension. Conclusions While SvMSCs produced fibrous tissue during default in vitro chondrogenesis, their fibrocartilage generation potential in the presence of static tension was significantly lower, compared with MCs. Our results support evaluation of cellular response to tensile stimulus as a decisive factor in determining the ideal cell source for fibrocartilage reconstruction.