Effects Of ADSCs&BMP-2on The Ischemic Capital Femoral Epiphysis Of Immature Rabbits

Objective:To evaluate the combined effects of ADSCs and BMP-2on avascular necrosis of the femoral head epiphysis.Methods:1. Cell experiment part:After reviving and passaging, ADSCs of second generation were marked by BrdU; and treat the cells with MTT test and Alizarin red stain test.2. Animal experiment part:45immature New Zealand rabbits were randomly divided into5groups, and were made into Perthes disease models by disrupting the blood supply to femoral head epiphysis. After2weeks, group A was treated with sham-operation; group B was treated with drilling, group C was treated with ADSCs after drilling; group D was treated with BMP-2; and group E was treated with ADSCs and BMP-2. At4,6and10weeks following the molding operation, every group was tested by MRI, and X-ray test, histologic examination, immunofluorescence assay were taken after femoral heads were harvested. All results were analyzed.Results:1. Cell experiment part:(1) ADSCs grew well and did not spontaneously differentiate.(2) About90%of ADSCs were marked by BrdU, and had good ability of proliferation and osteoblast differentiation.2. Animal experiment part:(1)X-ray test:At6weeks after molding operation, capital femoral epiphyseal quotient of group C, D and E were better than group A and B (p<0.05). At10weeks, group D was better than group A and B, and group C and E were significantly better than group A and B (p<0.01).(2)MR:At6and10weeks after molding operation, spots of necrosis were observed in group A and B, and the hip joint space was widened. There were mixed signals in femoral head epiphysis of group C, D, E at4and6weeks. And the signals of group C and E turned to be uniform, and the hip joint structure was good at10weeks. But the signal in femoral head epiphysis of group D was still a little mixed, and the hip joint space turned to be a bit widened.(3)Histologic examination:At4weeks, bone trabecular area of group C, D, E was higher than group A and B (p<0.05), and group D was higher than group A and B at6and10weeks (p<0.05), while group C and E was significantly higher than group A and B (p<0.01). Growth plate height of all groups is nearly the same (p>0.05).(4)The immunofluorescence assay of Group C and E showed that BrdU positive cells were observed in every sample; and there were BrdU positive cells in bone trabecular at4and8weeks after cell transplantation.Conclusion:For avascular necrosis of the femoral head epiphysis in immature rabbits caused by vascular injury, treating with ADSCs and BMP-2after drilling through growth plate can not only increase the revascularization but also promote bone formation, and then prevent or retard femoral head deformity.