Chronic skeletal unloading of the rat femur: mechanisms and functional consequences of vascular remodeling.
Chronic skeletal unloading of the rat femur: mechanisms and functional consequences of vascular remodeling.
复制标题
大鼠股骨的慢性骨骼卸载：血管重塑的机制和功能后果。
DOI：
10.1016/j.bone.2013.09.003
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发表时间：
2013
期刊：
影响因子：
4.1
通讯作者：
Delp,MichaelD
中科院分区：
文献类型：
--
作者：
Stabley,JohnN;Prisby,RhondaD;Behnke,BradleyJ;Delp,MichaelD
慢性骨骼卸载减少后肢骨血流量。本研究的目的是确定1）骨骼卸载7天和14天是否会改变股骨和骨髓血流以及重新加载期间的血管阻力，以及2）骨灌注的假定变化是否与股骨主要营养动脉（PNA）的总体结构重塑相关。将6月龄雄性Sprague-Dawley大鼠分为7天或14天后肢去负荷（HU）或负重对照组。在卸载处理后站立（重新加载）10分钟后测量骨灌注。组织形态计量学测定PNA中膜壁厚度和最大直径。利用骨血流量、动脉压和PNA结构特征计算动脉切应力和周壁应力。在重新加载过程中，股骨灌注较低，在远端干骺端区域的7天HU大鼠，并在近端和远端干骺端，骨干和骨干骨髓的14天HU动物相对于对照组大鼠。血管阻力也较高，在所有地区的股骨在14天HU大鼠在重新加载过程中相对于对照组动物。14-dHU大鼠PNAs管腔内径（138 ± 5 μm）小于对照组PNAs管腔内径（162 ± 6 μm），中膜厚度（14.3 ± 0.6 μm）小于对照组（18.0 ± 0.8 μm）。剪切应力和周向应力的减少发生在PNA与HU，后来回到控制水平的PNA最大直径和壁厚的减少，分别。结果表明，慢性骨骼卸载会削弱增加血液流量和向骨骼和骨髓输送营养的能力，并立即进行急性重新加载，部分原因是骨阻力血管系统的重塑。
Chronic skeletal unloading diminishes hindlimb bone blood flow. The purpose of the present investigation was to determine 1) whether 7 and 14 days of skeletal unloading alter femoral bone and marrow blood flow and vascular resistance during reloading, and 2) whether putative changes in bone perfusion are associated with a gross structural remodeling of the principal nutrient artery (PNA) of the femur. Six-month old male Sprague–Dawley rats were assigned to 7-d or 14-d hindlimb unloading (HU) or weight-bearing control groups. Bone perfusion was measured following 10 min of standing (reloading) following the unloading treatment. Histomorphometry was used to determine PNA media wall thickness and maximal diameter. Bone blood flow, arterial pressure and PNA structural characteristics were used to calculate arterial shear stress and circumferential wall stress. During reloading, femoral perfusion was lower in the distal metaphyseal region of 7-d HU rats, and in the proximal and distal metaphyses, diaphysis and diaphyseal marrow of 14-d HU animals relative to that in control rats. Vascular resistance was also higher in all regions of the femur in 14-d HU rats during reloading relative to control animals. Intraluminal diameter of PNAs from 14-d HU rats (138 ± 5 μm) was smaller than that of control PNAs (162 ± 6 μm), and medial wall thickness was thinner in PNAs from 14-d HU (14.3 ± 0.6 μm) versus that of control (18.0 ± 0.8 μm) rats. Decreases in both shear stress and circumferential stress occurred in the PNA with HU that later returned to control levels with the reductions in PNA maximal diameter and wall thickness, respectively. The results demonstrate that chronic skeletal unloading attenuates the ability to increase blood flow and nutrient delivery to bone and marrow with immediate acute reloading due, in part, to a remodeling of the bone resistance vasculature.