Mackey K, Meyer M C, Stirewalt W S, Starcher B C, McLaughlin M K
Department of Pediatrics, University of Cincinnati College of Medicine, Ohio 45267-0541.
Am J Physiol. 1992 Jul;263(1 Pt 2):R2-8. doi: 10.1152/ajpregu.1992.263.1.R2.
We tested the hypothesis that the systemic resistance vasculature of the rat is remodeled during pregnancy as evidenced by significant alterations in the passive mechanical properties and extracellular matrix proteins in mesenteric arteries. Mechanical characteristics were determined for arteries from 20-day pregnant rats (n = 6) and age-matched controls (n = 5). Lumen diameter and wall thickness were measured in pressurized arteries (250-microns diameter) using a dimension analyzing system. Distensibility (the relative change in diameter per unit change in pressure) was less in the arteries from the pregnant rats (P less than 0.01). The calculated stress-strain relationships and elastic moduli indicated that the arteries were less stiff by late gestation (P less than 0.05). Ultramicro amino acid analysis and radioimmunoassay were used to measure hydroxyproline, desmosine, and leucine as indicators of collagen, elastin, and total protein, respectively, in similar-sized arteries. Hydroxyproline/leucine (index of collagen) and desmosine/leucine (elastin concentration) decreased 19 and 15% by late gestation (P less than 0.05). The significant alterations in passive mechanics and in extracellular protein content support the concept that arterial wall remodeling in the peripheral vasculature may be one component of the cardiovascular adaptations during pregnancy.
大鼠的全身阻力血管系统在孕期会发生重塑，肠系膜动脉的被动力学特性和细胞外基质蛋白的显著改变即为明证。测定了20天孕期大鼠（n = 6）和年龄匹配的对照组大鼠（n = 5）动脉的力学特性。使用尺寸分析系统在加压动脉（直径250微米）中测量管腔直径和壁厚。妊娠大鼠动脉的扩张性（压力单位变化时直径的相对变化）较小（P < 0.01）。计算得出的应力-应变关系和弹性模量表明，到妊娠后期动脉的硬度降低（P < 0.05）。采用超微氨基酸分析和放射免疫测定法，分别测量了大小相似的动脉中作为胶原蛋白、弹性蛋白和总蛋白指标的羟脯氨酸、锁链素和亮氨酸。到妊娠后期，羟脯氨酸/亮氨酸（胶原蛋白指标）和锁链素/亮氨酸（弹性蛋白浓度）分别下降了19%和15%（P < 0.05）。被动力学和细胞外蛋白含量的显著改变支持了这样一种观点，即外周血管系统的动脉壁重塑可能是孕期心血管适应性变化的一个组成部分。
