The John B. Pierce Laboratory, New Haven, Connecticut, USA.
Microcirculation. 2012 May;19(4):306-15. doi: 10.1111/j.1549-8719.2012.00163.x.
Regional blood flow to the diaphragm muscle varies with the workload of inspiration. To provide anatomical insight into coupling between muscle fiber recruitment and oxygen supply, we tested whether arterioles are physically associated with motor nerve branches of the diaphragm.
Following vascular casting, intact diaphragm muscles of C57BL/6 and CD-1 mice were stained for motor innervation. Arteriolar networks and nerve networks were mapped (~2 μm resolution) to evaluate their physical proximity.
Neurovascular proximity was similar between muscle regions and mouse strains. Of total mapped nerve lengths (C57BL/6, 70 ± 15 mm; CD-1, 87 ± 13 mm), 80 ± 14% and 67 ± 10% were ≤250 μm from the nearest arteriole and associated predominantly with arterioles ≤45 μm in diameter. Distances to the nearest arteriole encompassing 50% of total nerve length (D(50)) were consistently within 200 μm. With nerve networks repositioned randomly within muscle borders, D(50) values nearly doubled (p < 0.05). Reference lines within anatomical boundaries reduced proximity to arterioles (p < 0.05) as they deviated from the original location of motor nerves.
Across two strains of mice, motor nerves and arterioles of the diaphragm muscle are more closely associated than can be explained by chance. We hypothesize that neurovascular proximity facilitates local perfusion upon muscle fiber recruitment.
膈肌的区域性血流随吸气负荷而变化。为了深入了解肌肉纤维募集与氧供应之间的耦合，我们测试了动脉是否与膈肌的运动神经分支在物理上有关联。
在血管铸型后，对 C57BL/6 和 CD-1 小鼠的完整膈肌肌肉进行运动神经支配染色。以~2 μm 的分辨率绘制动脉网络和神经网络，以评估它们的物理接近程度。
神经血管的接近程度在肌肉区域和小鼠品系之间相似。在总映射的神经长度中（C57BL/6，70 ± 15 mm；CD-1，87 ± 13 mm），80 ± 14%和 67 ± 10%分别距离最近的动脉<250 μm，并主要与直径≤45 μm的动脉相关。距离最近的包含 50%总神经长度的动脉（D(50)）始终在 200 μm 内。当神经网络在肌肉边界内随机重新定位时，D(50)值几乎增加了一倍（p < 0.05）。在解剖学边界内的参考线更接近动脉（p < 0.05），因为它们偏离了运动神经的原始位置。
在两种小鼠品系中，膈肌的运动神经和动脉比随机接近的可能性更为接近。我们假设神经血管的接近程度有助于肌肉纤维募集时的局部灌注。
