STRETCH AS A GROWTH STIMULUS IN VASCULAR SMOOTH MUSCLE

有几种疾病会引起肺部的病理变化， 血管床 这种“肺血管疾病”可能导致右 心室衰竭和过早死亡 的细胞事件 这些病理变化的基础是知之甚少，但它 血管的异常生长和合成功能 平滑肌很重要。 虽然不知道是什么 调节这种异常的平滑肌功能，临床和 实验观察表明，机械刺激可能发挥作用， 一个重要的角色 有人建议检查的假设，拉伸作为一个 对肺血管平滑肌的生长刺激。 先前 特征性的，培养的大鼠肺平滑肌细胞 动脉将生长在胶原蛋白涂层的硅胶膜上， 进行步进或重复拉伸以确定：1）是否 拉伸影响有丝分裂的速率（通过3 H-胸苷），细胞大小， 和蛋白质含量。 生长相关原核表达 癌基因c-myc和c-fos（通过北方印迹分析）也将被 测定 2.如果拉伸调节了整个蛋白质的产生 (by 3 H-亮氨酸和35 S-甲硫氨酸），以及这是否受到影响 通过改变蛋白质合成的速率（测量总的和 核糖体RNA、氨基酸摄取和S6激酶活化）和/或 降解（使用3 H-苯丙氨酸）。 3)如果拉伸调节 收缩蛋白（肌球蛋白重链和调节轻链， 平滑肌特异性α肌动蛋白和平滑肌特异性 α-原肌球蛋白）信使或蛋白质产生，和/或胶原蛋白 和弹性蛋白（凝胶电泳和免疫沉淀） 合成. 4)如果像预期的那样，拉伸确实有一个 生理效应，将研究其机制， 与生长相关的细胞内“信号”（Na+流入， 细胞内pH和（Ca++），以及Na+/K+ ATP酶的活化） 成为调查的最初焦点。 拟议研究的最初目标是确定 平滑肌功能可能受到拉伸的影响， 探索拉伸影响细胞生理的机制。 从长远来看，人们希望探测器能够发展成 使在体内探索机械的作用成为可能， 血管病理学中的变形。

Several disorders cause pathological changes in the pulmonary vascular bed. This "pulmonary vascular disease" may lead to right ventricular failure and premature death. The cellular events underlying these pathologic changes are poorly understood, but it is clear that abnormal growth and synthetic function of vascular smooth muscle are important. Although it is not known what modulates this abnormal smooth muscle function, clinical and experimental observations suggest that mechanical stimuli may play an important role. It is proposed to examine the hypothesis that stretch acts as a growth stimulus for pulmonary vascular smooth muscle. Previously characterized, cultured smooth muscle cells from rat pulmonary artery will be grown on a collagen-coated silicone membrane and subjected to step or repetitive stretch to determine: 1) Whether stretch affects the rate of mitosis (by 3H-thymidine), cell size, and protein content. Expression of the growth-associated proto- oncogenes c-myc and c-fos (by Northern blot analysis) will also be determined. 2. If stretch modulates overall protein production (by 3H-leucine and 35S-methionine), and whether this is effected by an altered rate of protein synthesis (measurement of total and ribosomal RNA, amino acid uptake, and S6 kinase activation) and/or degradation (using 3H-phenylalanine). 3) If stretch modulates contractile protein (myosin heavy and regulatory light chains, smooth muscle specific alpha actin, and smooth muscle specific alpha-tropomyosin) message or protein production, and/or collagen and elastin (gel electrophoresis and immunoprecipitation) synthesis. 4) If, as anticipated, stretch does have a physiological effect(s), its mechanism will be studied, with intracellular "signals" linked with growth (Na+ influx, intracellular pH and (Ca++), and activation of Na+/K+ ATP-ase) being the initial focus of investigation. The initial goal of the proposed studies is to determine which smooth muscle functions may be influenced by stretch, and to explore the mechanism(s) by which stretch affects cell physiology. Over the longer run, it is hoped that probes may be developed to make possible in vivo explorations of the role of mechanical deformation in vascular pathology.