MUSCLE CAPILLARY GEOMETRY, FLOW, AND OXYGEN TRANSFER

肌肉毛细血管的几何形状、流量和氧气传输

基本信息

批准号：
6389281
负责人：
DAVID C POOLE
金额：
$ 20.06万
依托单位：
KANSAS STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-07-01 至 2004-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6389281
关键词：
blood chemistry capillary cardiovascular function citrate synthase congestive heart failure diabetes mellitus diaphragm emphysema enzyme activity hamsters laboratory rat microcirculation muscle function radioactive microsphere technique respiratory function sarcomeres striated muscles vasodilation

项目摘要

DESCRIPTION (Adapted from the applicant's abstract): Effective O2 diffusion from the red blood cell to the muscle fiber is necessary to sustain cellular integrity and support oxidative function. There is increasing evidence that the principal resistance to O2 diffusion in skeletal muscle is extracellular. Under various physiological and pathological conditions, O2 diffusion is impaired resulting in muscle fatigue/failure and sometimes degenerative changes. Morphometric techniques have described the consequences of acute and chronic perturbations on capillary geometry. However, the effects of these changes on RBC hemodynamics, O2 exchange and muscle function have not been determined. The objective of the proposed investigations is to utilize established models of pathophysiological conditions to reconfigure capillary geometry and determine the relationships between capillary geometry, capillary hemodynamics, O2 exchange and muscle function. Specifically, it is hypothesized that capillary adaptations (reduced luminal diameter, involution, enhanced stretch) found in skeletal muscle of animals with diabetes, or those suffering from chronic heart failure, will act to impair RBC flux and augment RBC distribution heterogeneity thereby reducing blood-tissue O2 exchange and muscle performance. Two muscles of similar fiber type but differing in oxidative capacity (spinotrapezius and diaphragm) will be utilized. Experimental conditions are designed to stress the capacity for muscle blood flow and O2 exchange (vasodilation, hypoxemia/hyperoxemia, muscle contractions). Local vasodilation will be used to distinguish between arteriolar vasoregulatory effects and those arising from capillary geometrical alterations. Microvascular and muscle function will be assessed using intravital microscopy, phosphorescence quenching (microvascular PO2) and muscle tension measurements. These studies will combine established optical, phosphorescence and functional technologies to investigate the capacity for capillary geometrical changes to perturb muscle O2 exchange to obtain information regarding the role of capillary geometry in facilitating muscle O2 delivery in health and a series of common disease states.

描述（改编自申请人的摘要）：有效的O2扩散从红细胞到肌肉纤维是维持细胞的必要条件完整性和支持氧化功能。有越来越多的证据表明骨骼肌中O2扩散的主要抵抗力为细胞外。在各种生理和病理条件下，O2 扩散受到损害，导致肌肉疲劳/失败，有时退化性变化。形态计量技术已经描述了急性和慢性扰动对毛细血管几何形状的后果。但是，这些变化对RBC血液动力学，O2交换和尚未确定肌肉功能。提议的目标研究是利用已建立的病理生理模型重新配置毛细管几何形状并确定关系的条件在毛细管几何形状，毛细血管血液动力学，O2交换和肌肉之间功能。具体来说，假设毛细管适应（减少腔直径，相互事，增强的拉伸）在骨骼中发现患有糖尿病的动物或患有慢性心脏的动物的肌肉失败将削弱RBC通量和增强RBC分布异质性，从而减少血液组织O2交换和肌肉表现。两种相似纤维类型的肌肉，但氧化有所不同容量（Spinotrapezius和diaphragm）将被使用。实验设计的条件是为压力肌肉血流和O2的能力交换（血管舒张，低氧血症/高氧血症，肌肉收缩）。当地的血管舒张将用于区分小动脉血管调节影响和毛细血管几何改变产生的影响。微血管和肌肉功能将使用插入性评估显微镜，磷光猝灭（微血管PO2）和肌肉张力测量。这些研究将结合既定的光学，磷光和功能技术研究能力毛细血管几何变化，以驱动肌肉O2交换以获得有关毛细血管几何作用在促进肌肉中的作用的信息 O2在健康和一系列普通疾病状态中的递送。