Study On Evaluating SRY As A Engrafting Track Of Bone Marrow Mesenchymal Stem Cell Transplantation For Repairing Osteonecrosis Of Femoral Head

Objective To evaluate SRY as a engrafting track of the transplanted bone marrow mesenchymal stem cells (BMSCs) survival and new bone formation in the osteonecrosis of the femoral head. Methods Forty-nine 3-month-old New Zealand White rabbits were included, weighing 2-2.5 Kg, 48 female and 1 male. BMSCs of the rabbits were isolated by density gradient separation method, the third passage cells were marked by DiI. The animal model of ONFH were established with forty eight female rabbits by injecting liquid nitrogen, and femoral head was not dislocated, which were divided into 3 groups, 16 rabbits in each group, group A only established animal model as control, autologous BMSCs marked by DiI was transplanted in the ONFH models of the group B. Allogenic BMSCs marked by DiI was transplanted in ONFH models of the group C. The femoral head were observed by X-ray, HE staining and Masson trichrome staining and the regenerating trabecular volume percentages were determined at 2, 4, 6 and 8 weeks after operation respectively. The examples of the heart, lung, liver, spleen and kidney were obtained. The transplanted BMSCs were traced by fluorescence microscope, the SRY gene expression was detected by polymerase chain reaction (PCR) for cells survival. Results The X-ray showed necrosis in the femoral head of group A gradually. HE and Masson trichrome staining results showed that compared with the group A, the recovery condition of the necrotic femoral head in the group B and C was better. At each time-point of group B and C, the regenerating trabecular volume percentages were higher than that of the group A significantly. The result between group B and C was inconspicuous. Cells marked by DiI were not been founded in the tissue of the heart, lung, liver, spleen and kidney at each time point. PCR showed that the expression of SRY gene was not observed at the heart, lung, liver, spleen and kidney of three groups at each time point. The expression of SRY gene was clearly identified in the femoral head of all 16 rabbits in the group B at each time point. Conclusion Allografting of bone marrow mesenchymal stem cells transplanted into the femoral head can survive and induce new bone formation without redistribution. Both intramembranous ossification and endochondral ossification, cartilaginous ossification is showed in the femoral head by in situ hybridization for SRY.