Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
Acta Orthop. 2010 Oct;81(5):639-46. doi: 10.3109/17453674.2010.504609.
Autonomic neuropeptide Y (NPY) is involved in local bone remodeling via the central nervous system. However, the role of peripheral neuronal NPY in fracture healing is not known. We investigated the relationship between bone healing and side-specific occurrence of NPY in angular and straight fractures.
Tibial fractures in Sprague-Dawley rats were fixed with intramedullary pins in straight alignment and anterior angulation. The samples were analyzed by radiography, histology, and immunohistochemistry (IHC) between 3 and 56 days postfracture.
In the angular fractures, radiography and histology showed a 3.5-fold increase in callus thickness on the concave side compared to the convex side at day 21, whereas a 0.2-fold reduction in callus thickness was seen on the convex side between days 21 and 56. IHC showed regenerating NPY fibers in the callus and woven bone in both fractures at day 7. In angular fractures, a 5-fold increase in NPY fibers was observed on the concave side compared to the convex side at 7 days, whereas a 6-fold increase in NPY fibers was seen on the convex side between 21 and 56 days; only a 0.1-fold increase in NPY fibers was seen on the concave side during the same time period. In straight fractures, similar bony and neuronal changes were observed on both sides.
The increase in NPY innervation on the convex side appears to correlate with the loss of callus thickness on the same side in angular fractures. Our results highlight the probable function of the peripheral NPY system in local bone remodeling.
自主神经肽 Y（NPY）通过中枢神经系统参与局部骨重塑。然而，外周神经元 NPY 在骨折愈合中的作用尚不清楚。我们研究了骨愈合与 NPY 在角状和直骨折中侧特异性出现之间的关系。
在 Sprague-Dawley 大鼠的胫骨骨折中，采用髓内针以直对线和前向成角固定。在骨折后 3 至 56 天之间通过放射照相术、组织学和免疫组织化学（IHC）分析样本。
在角状骨折中，放射照相术和组织学显示在第 21 天，凹侧的骨痂厚度比凸侧增加了 3.5 倍，而在第 21 天至第 56 天之间，凸侧的骨痂厚度减少了 0.2 倍。IHC 在两种骨折中均在第 7 天显示出在骨痂和编织骨中再生的 NPY 纤维。在角状骨折中，与凸侧相比，凹侧的 NPY 纤维在第 7 天增加了 5 倍，而在第 21 天至第 56 天之间，凸侧的 NPY 纤维增加了 6 倍；在同一时期，凹侧的 NPY 纤维仅增加了 0.1 倍。在直形骨折中，在两侧均观察到类似的骨骼和神经变化。
凸侧 NPY 支配的增加似乎与角状骨折中同一侧骨痂厚度的丧失相关。我们的结果强调了外周 NPY 系统在局部骨重塑中的可能作用。
