An effective approach to cartilage regeneration using antler stem cell-conditioned medium.

Articular cartilage has a low capacity for self-regeneration. Therefore, stem cell therapy has been proposed and is gaining momentum. Antler can self-repair and its cartilaginous tissue can grow at an unprecedented rate (Up to 2 cm/day) and antler regeneration is based on antler stem cells. Therefore, we predicted that antler stem cells or their paracrine factors might be a good source for promoting cartilage repair. In this study, we prepared conditioned medium from antler stem cells (ASC-CM) and evaluated its effect. We implanted the medium into rat cartilage defects and assessed its capacity to promote cartilage repair. The protein composition of ASC-CM was analyzed using via DIA assay. ASC-CM can strongly promote chondrocyte proliferation in vitro; it significantly up-regulates the expression of chondrogenesis-related genes (Aggrecan, Col II, and Sox-9) and promotes glycosaminoglycan formation and type II collagen deposition in cartilaginous tissue; meanwhile up-regulate the apoptosis suppressor gene NAMPT and down-regulate apoptosis gene BAX. In vivo, cartilage defect in rats was significantly repaired using ASC-CM. The compositions of ASC-CM were got and some key proteins such as S100A4 were identified by bioinformatics analysis. The ASC-CM can promote the proliferation of rat-chondrocytes, maintain the chondrocyte phenotype, and inhibit apoptosis of rat-chondrocytes. Therefore, it can promote cartilage repair.