Objective To evaluate the effect of human bone morphogenetic protein 2 (hBMP-2)/Bone Mesenchymal Stem Cells (BMSCs)/demineralized bone matrix(DBM) on repairing rabbits’femoral head after necrosis and to explore the new treatments for femoral head necrosis. Methods Femoral head necrosis models was established by clinical core decom?pression combined with liquid nitrogen frozen. Then, animals were randomly devided into 4 groups (n=12 per group):Group A were not implanted anything as control group, Group B were implanted with DBM. Group C were implanted with hBMP-2/DBM. Group D were implanted with hBMP-2/BMSCs/DBM. Four rabbits from each group were sacrificed at 4,8 and 12 weeks after surgery to evaluate the the repairing effect of Osteonecrosis of the femoral head (ONFH) through X-ray examina?tion, observation of the specimen and HE staining. Results X-ray revealed defect of femoral head in Group A without clear bone formation. There is a little fibrous hyperplasia and no obvious osteogenic response. By contrast, the femoral head defect areas became fuzzy in group B, group C and group D with new bone trabeculars. And the regenerate phenomenons of group D were significantly better than that of group B and group C of the same time point. As to the Lane-Sandhu X Ray scores, it is lower in group A than that in group B;It is lower in group C than that in group D(P<0.05). There is no statistical difference between Group B and Group C. General observation of the specimen revealed that the femoral head of group A collapsed with drilling holes. The femoral heads of group B and group C showed no collapse but the drilling holes existed. Femoral head in group D was not collapsed and the drilling holes disappeared. HE staining showed that bone trabeculars became ne?crotic and fragmented in Group A with a lot of air trapped cells. There were newborn immature bone trabeculars and osteo? blasts in group B and group C. Group D were of large number of bone cells, fat cells, and newborn mature bone trabeculars. The ratio of empty lacuna is higher in Group A than that in Group B;it is higher in Group C than that in Group D(P<0.05). Conclusion hBMP-2/BMSCs/DBM can induce BMSCs differentiation into osteoblasts after being implanted. It has good re?pairing effect on ONFH with good application prospect.

Objective To study the effects of short-term cryopreservation on the proliferation ,bio-characteristics and osteogenic capability of rabbit BMSCs and lay the foundation for the further study .Methods The 5th generation of rabbit BMSCs were cryo-preservated by liquid nitrogen for 30 days ,and then thawing the cells to culture it to the 10th generation in vitro ,put the non-cryo-preservated and the same generation BMSCs as the control group .The MTT ,cell cycle ,cell surface marker ,the content of ALP and the immunohistochemical staining for collagen typeⅠ and alizarin red staining for calcium after differentiation induced by osteogene-sis were used to evaluate the proliferation ,bio-characteristic and osteogenic differentiation capability of rabbit BMSCs .Results The growth incubation period of BMSCs after cryopreservated was extended ,but it gradually recover through serial passage .The prolif-eration index and the proportion of BMSCs in G1 phase were 42 .9% ± 3 .4% and 57 .0% ± 3 .4% respectively .The positive rate of cell surface marker of CD44 was 93 .62% ± 1 .05% without expression of CD45 .The contents of ALP(U/gprot) were 6 .73 ± 1 .92 and 15 .99 ± 4 .36 in BMSCs after 7th day and 14th day with osteogenic induction ,respectively .The collagen typeⅠ and alizarin red staining for calcium indicated positive at BMSCs after 14th day and 21th day with osteogenic induction ,respectively .These results showed no significant difference compared with the control group (P>0 .05) .Conclusion Short-term cryopreservation has no obvi-ous impacts on the proliferation ,bio-characteristic and osteogenic capability of BMSCs and it could be used for further study .

Objective To observe the biocompatibility of rabbit bone marrow mesenchymal stem cells (BMSCs)combined with allogeneic decalcified bone matrix(DBM)after transfecting adenoviral recombinant human bone morphogenetic protein-2(Ad-rhBMP-2).Methods The rabbit allogeneic DBM material was prepared according to the Ursit method.After transfecting Ad-BMP-2 on rabbit bone marrow mesenchymal stem cells,the immunohistochemical was used to detect the expression of BMP-2 in the transfected cells;after 48 h of transfection,the cells were planted on the allograft DBM,then the scanning electron microscopy was used to observe the cell growth and adhesion condition on material,and the proliferation condition of BMSCs was detected by MTT. Results After 48 h of adenoviral transfection,BMSCs could express BMP-2 successfully.The scanning electron microscopy showed that the cells after transfection adhered well and massively proliferated on DBM material.The MTT assay showed that the prolifer-ation condition of the cells after transfection planted on DBM was normal,which showed no statistically significant difference when compared with the control group (P >0.05).Conclusion The Ad-BMP-2 transfection on BMSCs is well biocompatible to allogene-ic DBM.