Roth N M, Sontag M R, Kiani M F
School of Biomedical Engineering, University of Tennessee Health Science Center, Memphis 38163, USA.
Radiat Res. 1999 Mar;151(3):270-7.
Microvascular networks, which control the delivery of oxygen and nutrients and the removal of metabolic waste, are the most sensitive part of the vascular system to ionizing radiation. Structural and functional changes in microvascular networks were studied in locally irradiated (single 10-Gy dose) hamster cremaster muscles observed 3, 7 and 30 days post-irradiation. Networks were selected in reference to a well-defined location in the tissue to reduce heterogeneity due to spatial variations. Intravital microscopy was used to measure structural and functional parameters in vivo. A factorial design was used to examine the effects of radiation status, time postirradiation, and network vessel type on the structure and function of microvascular networks. While the diameter of microvessels in control animals increased significantly with age, vessel diameter in irradiated vessels decreased significantly with age. Red blood cell velocity in irradiated networks at 3 and 30 days postirradiation was significantly lower than in control networks. There was a significant decrease in capillary surface area and a significant increase in vessel hematocrit in irradiated animals. Blood flow in irradiated vessels was significantly lower than in control vessels. Changes in functional parameters were evident at 3 days postirradiation while changes in structural parameters occurred later. All vessel types were not damaged equally by radiation at every time examined.
微血管网络控制着氧气和营养物质的输送以及代谢废物的清除，是血管系统中对电离辐射最敏感的部分。研究了局部照射（单次10 Gy剂量）的仓鼠提睾肌在照射后3天、7天和30天观察到的微血管网络的结构和功能变化。为减少因空间差异导致的异质性，根据组织中明确界定的位置选择网络。采用活体显微镜在体内测量结构和功能参数。采用析因设计来研究辐射状态、照射后时间和网络血管类型对微血管网络结构和功能的影响。对照动物的微血管直径随年龄显著增加，而照射血管的直径随年龄显著减小。照射后3天和30天，照射网络中的红细胞速度显著低于对照网络。照射动物的毛细血管表面积显著减少，血管血细胞比容显著增加。照射血管中的血流显著低于对照血管。功能参数的变化在照射后3天明显，而结构参数的变化则出现得较晚。在每次检查时，并非所有血管类型都受到同等程度的辐射损伤。
