Abstract:

Abstract：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.

Key words: femur head necrosis, disease models, animal, adenovirus, bone morphogenetic protein -2, demineralized
bone matrix, bone marrow mesenchymal stem cells, hBMP-2/BMSCs/DBM