Dhillon D P, Barer G R, Walsh M
Q J Exp Physiol. 1984 Apr;69(2):301-17. doi: 10.1113/expphysiol.1984.sp002807.
Rats were subjected to chronic hypoxia (10% O2) or hypoxia and hypercapnia (10% O2 + 4% CO2) for 3-4 weeks and their carotid bodies (twenty-three from twenty rats) were compared with those of litter-mate controls. Both chronic exposures, which simulated high altitude or chronic lung disease, caused a 4-10-fold increase in carotid body volume. The larger increases were attributed to higher fixation-perfusion pressures. The organs were fixed by perfusion with glutaraldehyde. Semi-thin (1 micron) sections for light microscopy and ultra-thin sections for electron microscopy were cut at regular intervals and were examined by stereological techniques to determine the nature of the enlargement. The proportion occupied by blood vessels was much increased in both chronic hypoxia and hypoxia plus hypercapnia; the endothelium appeared stretched with conspicuous fenestrations. There were increased numbers of endothelial cells which suggested new growth as well as stretching of endothelium and the mean transectional area of the vessels was increased. The mean surface area of blood vessels per unit area of carotid body was unaltered but the total surface area of blood vessels in the whole carotid body was greatly increased. Both the Type 1 cell nucleus and cytoplasm were increased in size. The proportion nucleus/cytoplasm was unaltered in hypoxia but reduced in hypoxia plus hypercapnia. There were fewer Type 1 cell nuclei per unit area but the estimated total number of Type 1 cell nuclei per carotid body was increased 2-4-fold; this was interpreted as Type 1 cell hyperplasia. Some of the dense-cored vesicles in Type 1 cells were enlarged with eccentric dense cores but their number per unit area of cytoplasm was decreased. Their mean size was not significantly altered. However, the total number of vesicles per carotid body was presumed to be increased because their decreased density in the cell was offset by a greater increase in total Type 1 cell volume. The harmonic and arithmetic mean distances between endothelium and the boundary of glomus tissue were significantly reduced. The harmonic mean distance is an indication of the diffusion distance for gases to and from blood and glomus tissue. The arithmetic mean distance is a measure of the amount of tissue in between. The significance of the vascular enlargement and hyperplasia and the Type 1 cell hyperplasia cannot be assessed at present. We do not know if enlargement is associated with the same, greater, or lesser activity of the organ for a given stimulus.
将大鼠置于慢性低氧（10%氧气）或低氧加高碳酸血症（10%氧气 + 4%二氧化碳）环境中3 - 4周，将其颈动脉体（来自20只大鼠的23个）与同窝对照大鼠的颈动脉体进行比较。这两种模拟高原或慢性肺部疾病的慢性暴露，均使颈动脉体体积增加了4 - 10倍。增加幅度较大归因于更高的固定灌注压力。通过用戊二醛灌注来固定器官。定期切取用于光学显微镜观察的半薄（1微米）切片和用于电子显微镜观察的超薄切片，并采用体视学技术进行检查，以确定增大的性质。在慢性低氧和低氧加高碳酸血症两种情况下，血管所占比例均大幅增加；内皮细胞似乎被拉伸，有明显的窗孔。内皮细胞数量增加，提示有新的生长以及内皮细胞的拉伸，并且血管的平均横截面积增大。每单位颈动脉体面积的血管平均表面积未改变，但整个颈动脉体中血管的总表面积大幅增加。1型细胞核和细胞质的大小均增加。在低氧情况下，核/质比例未改变，但在低氧加高碳酸血症时降低。每单位面积的1型细胞核数量减少，但每个颈动脉体中1型细胞核的估计总数增加了2 - 4倍；这被解释为1型细胞增生。1型细胞中的一些有致密核心的囊泡增大，核心偏心，但每单位细胞质面积中的数量减少。它们的平均大小没有显著改变。然而，每个颈动脉体中囊泡的总数被认为是增加的，因为细胞中其密度的降低被1型细胞总体积更大的增加所抵消。内皮细胞与球旁组织边界之间的调和平均距离和算术平均距离显著减小。调和平均距离表明气体进出血液和球旁组织的扩散距离。算术平均距离是对其间组织量的一种度量。目前尚无法评估血管增大和增生以及1型细胞增生的意义。我们不知道对于给定的刺激，增大是否与该器官相同、更强或更弱的活性相关。
