Parathyroid Hormone Enhanced The Therapeutic Effect Of Core Decompression On Glucocorticoid-induced Early Osteonecrosis

Background:Core decompression is a common treatment for early steroid-induced femoral head necrosis,but its prognosis has not been ideal.Parathyroid plays an active role in promoting bone formation.We hypothesize that parathyroid may enhance the effectiveness of core decompression in the treatment of early steroid-induced osteonecrosis.Method:Fifty-four healthy adult male rabbits were selected and 14 were used as controls.40 other rabbits were injected with methylprednisolone to induce osteonecrosis(4 rabbits died after modeling).Two weeks later,magnetic resonance scanning was performed to determine the success of the model.Core decompression was performed bilaterally in the distal femurs of rabbits in all rabbits,sixteen steroid-induced necrosis rabbits were treated with parathyroid for six weeks,the other sixteen steroid-induced necrosis rabbits were injected with saline.After 6 weeks,4 of the rabbits in the control group,the surgery group and parathyroid hormone combined surgery group were subjected to magnetic resonance scanning to observe the osteonecrosis at the femoral condyle.H&E staining and magnetic resonance scanning were used to observe the degree of necrosis.Micro-CT was performed to observe bone formation in core decompression tunnel.Biomechanics tests was conducted to evaluate the stiffness and maximum load.Immunohistochemical staining was used to evaluate angiogenesis.QPCR was performed to detect the expression of BMP-2,Runx2 and VEGF mRNA.Western Blot was used analyze the expression of BMP-2 and VEGF proteins.Result:Compared to the core decompression group,treatment of combining parathyroid and core decompression relieved edema in the femoral bone marrow.Bone density(162.46 ± 31.27 vs.103.98 ± 50.57 mg/cc,P = 0.021),bone volume/total volume(13.97± 3.37 vs 8.22 ± 4.56%,P = 0.018),trabecular number(1.05 ± 0.30 vs 0.60 ± 0.25,P =0.08)were significantly increased in the tunnel.Stiffness(100.40 ± 27.56 vs 52.65 ±18.07 N/m,P = 0.009)and maximum load(60.40 ± 20.45 vs 37.37 ± 9.27 N,P = 0.045)of the femur was enhanced significantly in biomechanical testing.Histological staining revealed that the necrotic osteocytes decreased,the number of vacuoles declined.Moreover,the number and diameter of blood vessels in the bone marrow increased.Compared with the core decompression group,the expression of BMP-2,RUNX2 and VEGF mRNA in the parathyroid-treated group elevated significantly(P<0.05).Western blot showed that the contents of BMP-2 and VEGF also increased.Conclusion:Parathyroid might be able to enhanced the treatment of core decompression by promoting osteogenesis and angiogenesis in early steroid-induced femoral head necrosis,which providing new ideas for clinical treatment.