백서모델에서 장기간 사용된 파미드로네이트가 골 강도 및 골절 치유에 미치는 영향

Abstract

Purpose: We investigated the effects of the long-term administration of pamidronate on long bone strength and fracture healing in a rat osteoporosis model. Materials and Methods: We performed bilateral ovariectomies in sixty-six 3-month-old female Sprague-Dawley rats. Three months after the ovariectomies, the animals were randomized into two groups. Disodium pamidronate or saline was injected into the rats every month for 6 months. The left femoral shafts were fractured by a closed fracture technique. Five weeks after the fractures, the rats were euthanized and both femurs were removed. We evaluated the mechanical properties of the normal and fractured femurs and the bone mineral densities of the right femoral heads. Pamidronate concentration was determined by high performance-liquid-chromatography. Results: The maximum strength and stiffness of the right femurs were 154.4±17.5 N, 452.5±122.8 N/㎜ in the pamidronate-treated group and 129.7±28.0 N, 378.6±126.2 N/㎜ in the control group (p＜0.05). The maximum strength of the calluses compared with the right femurs and the mean bone mineral density of the right femoral heads were 22.7±7.2%, 230±9 ㎎/㎠ in the pamidronate-treated group and 29.7±13.5%, 219±13 ㎎/㎠ in the control group (p＜0.05). Conclusion: Pamidronate effectively protected the femurs from bone resorption and preserved bone strength and stiffness after ovariectomies. However, fracture healing was impaired during the early stage of healing after long-term administration of pamidronate.