OBJECTIVETo explore the therapeutic effect of osteogenically induced adipose-derived stem cells (ADSCs) on vascular deprivation-induced osteonecrosis of the femoral head (ONFH) in rabbit model.

METHODSVascular deprivation-induced ONFH was established by intramuscular injection of methylpre- dnisolone, and vascular occlusion of the capital femoral epiphysis by electrocoagulation in adult New Zealand white rabbits. Eight weeks after the establishment of vascular deprivation-induced ONFH, animals were randomly divided into three equal groups. In Group A (control), no therapy was given. In Group B, core decompression was performed by drilling a hole (1.2 mm in diameter) from the outer cortex 2.5 cm distal to the proximal end of the greater trochanter. In Group C, 1 multiply 10(7) osteogenically induced ADSCs were resuspended in 0.5 ml PBS, and then injected directly into the femoral head. Femoral head specimens were obtained at postoperative 8 weeks. The bone formation and three-dimensional microstructure of the femoral head was evaluated by micro-computed tomography scans. Immunohistochemical analysis was performed to detect the expression of osteocalcin. Angiogenesis and repair of the femoral head were observed histologically.

RESULTSIn trabecular bone at the proximal femur region, the trabecular volume was higher in Group C (130.70 mm(3)+/-4.33 mm(3)) than that in Groups A (101.07 mm(3)+/-7.76 mm(3)) and B (107.89 mm(3)+/-8.68 mm(3), P less than 0.01). Bone volume was significantly increased in Group C (40.09 mm(3)+/-6.35 mm(3)) than in Groups A (29.65 mm(3)+/-4.61 mm(3)) and B (31.80 mm(3)+/-4.01 mm(3), P less than 0.01). The trabecular number was higher in Groups C (1.58+/-0.25) than other two groups (1.15+/-0.18, 1.16+/-0.21, P less than 0.01). Bone mineral density showed statistically significant difference between Groups C and A or B (375.38+/-23.06) mg HA/ccm, vs (313.73+/-19.30) mg HA/ccm and (316.09+/-16.45) mg HA/ccm, P less than 0.01). Histological examination indicated that there was more new bone formation in Group C than in other groups.

CONCLUSIONTreatment with autologous osteogeni-cally induced ADSCs transplantation results in an enhanced osteogenesis and microstructure of the vascular deprivation-induced osteonecrosis in rabbits.