Experimental Study Of Repairing Bone Defects With Different Concentration Nitric Oxide Combined With Freeze-dried Bone Allograft

Objective: To evaluate the effect of different concentration Nitric Oxide(NO) on repairing of large segemental bone defects.Methods: Segemental bone defects for 15mm were created in the 48 New Zealand rabbits on mid part of the right radius,and Nitroso-bovine serum albumin was made as nitric oxide donor.48 rabbits were divided into three groups,the defects being treated with three kinds of implants, A:low concentration nitroso-bovine serum albumin combined with freeze-dried bone allograft, B: high concentration nitroso-bovine serum albumin combined with freeze-dried bone allograft, C: single free-dried bone allograft as control. Radiographic and histologic examination was made and the amount of calcium in the defect area was tested at 3,6,9 and 12 weeks after operation. 12 weeks before killing the rabbits, the content of nitrite in the rabbits body was measured.Results: The results show Group A was better than Group B (P <0.01) and Group C (P <0.05) in the process of bone healing, and Group C was better than Group E(P <0.05).12 weeks after surgery,mean serum nitrite levels in Group B were higher than in Group A (P <0.05) and in Group C(P <0.01),the levels in Group A were higher than in the Group C (P <0.05).By 12 weeks,the defects in Group A were repaired completely and the medullary canal was recanalized.Conclusion: Low concentration applied NO with NO donor nitroso-bovine serum provided benefical effects to bone healing,high concentration Nitric Oxide had the restraining effects in the process of bone healing.