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HUMAN MESENCHYMAL STEM CELLS CULTURED IN A 3D-CLINOSTAT DIFFERENTIATE TO CHONDROCYTES AFTER TRANSPLANTATION.  Louis Yuge¹, Atsuko Okubo¹, Takashi Miyashita¹, Katsuko Kataoka², and Masamoto Kanno³ (¹Inst. of Health Sciences, ²Dept. of Anatomy, ³Dept. of Immunology: Graduate School  of Biomedical Sciences, Hiroshima Univ.)

   A 3D-clinostat is a multi-directional gravity device for simulating microgravity (10^-3G).  We cultured human mesenchymal stem cells (hMSC) in Dulbecco`s MEM for 3 days in the 3D-clinostat (group CL) or in 1G environment (group C), and the cell pellet was obtained.  The pellet of hMSC was 2-times lager in group CL than in group C.  The pellet of  both groups was further cultured in a chondrocyte differentiation medium for 2 weeks in 1G.  Type II collagen production was increased in group C, while it was not expressed in group CL.  Phosphorylation of MAPK/ERK was repressed in group CL, while total MAPK/ERK was not changed.  Then we transplanted the pellets into the cartilage defect made in the intercondylar fossa of the mouse femur.  After 2 weeks, necrosis of the transplanted cells from group C were often seen.  When the transplants were from group CL, necrosis was scaresely seen, and the transplants formed hyaline cartilage.  These results suggest that hMSC remain more undifferentiated in culture in a 3D-clinostat, which makes better differentiation after transplantation. 

(Supported by “Ground Research Announcement for Space Utilization” and Ministry of Education, Science, Sports, Culture and Technology of Japan)