Effects of blood flow and blood pressuere changes on the remodeling of arterial wall

通过动物实验，了解血流和/或血压变化对大鼠动脉壁尺寸和力学性质的影响，分析血管壁在应激反应中的功能适应和重塑现象.通过完全结扎双侧肾动脉（RA）之间的腹主动脉（AA）诱导高血压2天至8周。实验组左颈总动脉（LCCA）在收缩压下的周向壁应力维持在正常水平，这是由于管壁厚度增加，高血压激活了平滑肌细胞.分别结扎右侧颈总动脉（RCCA）和左侧颈外动脉2 ~ 8周，增加和减少LCCA的血流量。在血流增加的情况下，LCCA内径迅速增大，维持正常的壁剪切力;在血流减少的情况下，LCCA内径减小，但反应较慢.通过结扎双侧RA和RCCA之间的AA，同时在LCCA中诱导高血压和高血流量8周。LCCA的壁厚和内径增加，使壁周向应力和壁面切应力维持在正常水平。平滑肌细胞的活性增加，这些结果表明，动脉壁的功能适应和重塑，以响应应力，平滑肌细胞在这一现象中起着重要作用。

Chronic animal experiments have been done to know the effects of changes in blood flow and/or blood pressure on the dimensions and mechanical properties of the rat arterial wall, aiming to analyze the phenomena of functional adaptation and remodeling of vascular wall which occurs in response to stresses.1. Hypertension was induced by completely ligating the abdominal aorta (AA) between the bilateral renal arteries (RAs) for 2 days to 8 weeks. Wall stress in the circumferential direction of the left common carotid artery (LCCA) at the systolic blood pressure was maintained at a normal level for the experimental due to the increase in wall thickness, and hypertension activated smooth muscle cells.2. Blood flow in the LCCA was increased and decreased by ligating the right common carotid artery (RCCA) and the left external carotid artery, respectively, for 2 to 8 weeks. In the case of increased blood flow, the inner diameter of the LCCA increased rapidly, which served to maintain wall shear at a normal level; in the case of decreased blood flow, the diameter decreased, but the response was slower.3. Hypertension and high blood flow were simultaneously induced in the LCCA by ligating the AA between the bilateral RAs and the RCCA for 8 weeks. The wall thickness and inner of the LCCA increased so as to maintain wall circumferential stress and wall shear stress at each normal level. The activity of smooth muscle cells was increased.These results indicate that arterial wall functionally adapts itself and remodels in response to stresses, and that smooth muscle cells have an important role in this phenomenon.