writer：Jinwu Chen, Changyong Wang*, Shuanghong Lü, Junzheng Wu, Ximin Guo, Cuimi Duan, Lingzhi Dong, Ying S
keywords：Mesenchymal stem cell，Chondrogenesis，Microenvironment，Tissue engineering，In vivo differentiation，Sheep
source：期刊
specific source：Cell Tissue Res 319: 429–438 (2005.3)
Issue time：2005年

 The purpose of this study has been to investigate the possible effects of the normal joint cavity environment on chondrocytic differentiation of bone-marrow-derived mesenchymal stem cells(MSCs). Autologous bone marrow was aspirated from the iliac crest of male sheep. MSCs were purified, expanded, and labeled with the fluorescent dye PKH26. Labeled MSCs  were  then grown on a three-dimensional porous scaffold of poly (L-lactic-co-glycolic acid) in vitro and implanted into the joint cavity by a sur- gical procedure. At 4 or 8 weeks after implantation, the
implants were removed for histochemical and immuno-histochemical analysis. The cells labeled with red fluores-cent PKH26 in the implants expressed type II collagen and synthesized sulfated proteoglycans. However, the os-teoblast-specific marker, osteocalcin, was not detected by immunohistochemistry indicating that the implanted MSCs had not differentiated into osteoblasts by being directly exposed to the normal joint cavity. To investigate the possible factors involved in chondrocytic differentiation of MSCs further, we co-cultured sheep MSCs with the main components of the normal joint cavity, viz., synovial fluid or synovialcells, invitro. After 1or 2weeksof co-culture,the MSCs in both co-culture systems expressed markers of chondrogenesis. These results suggest that synovial fluid and synovium from normal joint cavity are important for the chondrocytic differentiation of adult bone-marrow-derived MSCs.