Therapeutic possibility of human fetal cartilage-derived progenitor cells in rat arthritis model

Fetal cartilage-derived progenitor cells (FCPCs) are a novel cell source for tissue engineering and cell therapy. Previously, cells from various fetal tissues were shown to have immune-modulatory activity just like mesenchymal stem cells. In this study, we investigated the cytotoxicity and therapeutic possibility of FCPCs as a potential cell therapy for arthritis in vivo. To evaluate the acute toxicity and safety, FCPCs were labeled with PKH-26 and subjected to intra-articular injection in rats. When examined at 1 and 2 weeks, the PKH-26 labeled FCPCs were observed only in the synovial membrane but not in other organs. There were no changes either in the white blood cells, red blood cells, and platelets in the hematological analysis and in the weight of the internal organs at 1 week. Therapeutic effect of FCPCs was examined on the complete Freund's adjuvant (CFA)-induced knee arthritis in rats in comparison with triamcinolone, a representative anti-arthritis drug. When inflammation-related edema of the arthritic knee joint was measured by the knee circumference, it increased significantly from the beginning and maintained until the end of measurement in the CFA group, which decreased back rapidly from 1 day in the triamcinolone group and slowly after 7 days in the FCPCs group. In the histological analysis, both triamcinolone and FCPCs decreased the infiltration of neutrophils and lymphocytes into the arthritic synovial membrane gradually at 3 and 7 days. These results suggest that FCPCs shows low toxicity or immune rejection when injected in the synovial cavity and have a therapeutic potential on the synovial arthritis in the rat model.