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

通过慢性动物实验，了解血流和/或血压的变化对大鼠动脉壁尺寸和力学性能的影响，旨在分析血管壁在应激反应中发生的功能适应和重构现象。将双侧肾动脉（RAs）间腹主动脉（AA）完全结扎，持续2天~ 8周。实验中，收缩压下左颈总动脉（LCCA）周向壁应力因壁厚增加而维持在正常水平，高血压激活平滑肌细胞。结扎右侧颈总动脉（RCCA）和左侧颈外动脉（RCCA） 2 ~ 8周后，LCCA血流增加和减少。在血流量增加的情况下，LCCA内径迅速增大，使壁剪力维持在正常水平；在血流减少的情况下，直径减小，但反应较慢。通过将双侧RAs与RCCA之间的AA结扎8周，在LCCA中同时诱导高血压和高血流量。LCCA的壁厚和内层增加，使壁面周向应力和壁面剪应力保持在各正常水平。平滑肌细胞活性增加。这些结果表明，动脉壁在应激反应中具有自我适应和重塑的功能，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.