Study of the osteogenic ability of mesenchymal stem cells in vivo / 中国矫形外科杂志

ABSTRACT

[Objective]To investigate the osteogenic ability in vivo of mesenchymal stem cells(MSCs).[Method]Ten-fifteen ml bone marrow aspirates were harvested from the iliac crest of sheep and enriched for MSCs by density gradient centrifugation over a Percoll cushion(1.073 g/ml).After cultured and proliferated,the tissue-engineered bones were constructed with these cells and seeded onto porous 13-tricalcium phosphate ceramics(13-TCP).Then,the constructs were implanted into left metatarsus defect(21 mm in length)of 8 sheep as an experimental group.Porous ?-TCP composed with bone marrow was implanted into defects of same size and position in 8 sheep as a control group.Sheep were sacrificed in the 6th,12th,and 24th week postoperatively,and the implanted samples were examined by radiograph,histology,and biomechanical analysis.[Result]New bone tissue was observed either radiographically or histologically at the defect area of experimental group as early as the 6th week postoperatively;but was not observed in the control group.Because of the new bone formed in a direct manner without progression through a cartilaginous process intermediately,osteoid tissue,woven bone and lamellar bone,occurred earlier in the experimental group than in the control group,in which the bone defects were repaired in a "creep substitution" manner.At the 24th week,radiographs and biomechanical tests revealed an almost complete repair of the defect in experimental group,but only a partial repair in the control group.[Conclusion]MSCs have good reproductive activity not only in vitro,but also in vivo.The new bone formed in a direct manner without progression through a cartilaginous process intermediately when MSCs were transplanted in vivo.The results demonstrated that MSCs was an excellent seed cells for bone tissue engineering.