[Bone healing in drill hole defects in spontaneously diabetic BB/OK rats. A histomorphometric and biomechanical...

The objective of this study was to examine changes in the histomorphometric and mechanical evaluation of the influence of the diabetic metabolic state on defect healing depending on the defect size in spontaneously diabetic BB/O(ttawa)K(arlsburg) rats. Based on blood glucose levels and postoperative insulin requirements, 120 spontaneously diabetic BB/OK rats were divided into groups with well-compensated or poorly compensated metabolic state. Sixty LEW.1A rats served as the normoglycemic controls. Bone defects of different sizes were created proximal to the knee joint space and then allowed to heal for 2, 4, and 6 weeks. Bone defect sizes > or =0.8 mm showed significant differences in the structural calculations and bone defect sizes > or =1.2 mm showed a significant decrease of all fluorochrome-based parameters of mineralization exclusively in the rats with poorly compensated diabetic metabolic state as well as significantly decreased values of biomechanical properties in comparison to the spontaneously diabetic rats with well-compensated metabolic states and to the control rats. Bone repair of minor bone defects is independent of the diabetic metabolic state in the spontaneously diabetic BB/OK rats. With controlled insulin therapy and resultant well-compensated diabetic metabolic state, severe mineralization and biomechanical disorders in healing of larger bone defects in the poorly compensated diabetic metabolic state of the experimental animal can be avoided.