Siqués Patricia, Brito Julio, León-Velarde Fabiola, Barrios Luis, Cruz Juan José De La, López Vasthi, Herruzo Rafael
Instituto de Estudios de Salud, Universidad Arturo Prat, Chile., Centro de Investigaciones del Hombre en el Desierto, Chile.
High Alt Med Biol. 2006 Spring;7(1):72-80. doi: 10.1089/ham.2006.7.72.
The aim of this study was to evaluate the effects of two periods of intermittent exposure to hypoxia (428 torr) in rats over 12 months. The conditions of CIH4x4 (4 days in hypoxia, 4 days in normoxia, n = 50) and CIH2x2 (2 days in hypoxia, 2 days in normoxia, n = 50) were selected for simulating in this animal model the chronic-intermittent exposure to high altitudes experienced by Andean miners. We assessed mortality, weight, hematological parameters, and time course of resting heart rate and systolic blood pressure. In general, mortality increased during the first month, with a tendency to stabilize during exposure; it was associated with lower weights and with higher hematocrit levels, making these possible predictor factors. Intermittence produced an increase in hematocrit and hemoglobin concentrations as previously seen in most hypoxic models, compared with normoxia (NX, n = 30), but attained lower levels compared with chronic hypoxia (CH, n = 28). CIH4x4 and CIH2x2 had similar sustained elevations of systolic blood pressure (171 +/- 3 and 174 +/- 2 mmHg, respectively) versus the basal level (163 +/- 3; 163 +/- 3 mmHg), whereas CH did not. Heart rate suffered an equally sustained decrease in all exposed groups (343 +/- 14 beats/min). Exposure to chronic-intermittent hypoxia led to a mild polycythemia and to a decrease in heart rate. The effects of hypoxia were already evident during the first month of exposure and attained a more pronounced expression and stabilization during the third month.
本研究的目的是评估大鼠在12个月内两个阶段间歇性暴露于低氧环境（428托）的影响。选择CIH4x4（低氧4天，常氧4天，n = 50）和CIH2x2（低氧2天，常氧2天，n = 50）条件来在该动物模型中模拟安第斯矿工所经历的慢性间歇性高海拔暴露。我们评估了死亡率、体重、血液学参数以及静息心率和收缩压的时间进程。总体而言，死亡率在第一个月增加，在暴露期间有稳定的趋势；它与较低体重和较高的血细胞比容水平相关，这些可能是预测因素。与常氧组（NX，n = 30）相比，间歇性暴露如大多数低氧模型中所见，导致血细胞比容和血红蛋白浓度增加，但与慢性低氧组（CH，n = 28）相比达到较低水平。CIH4x4和CIH2x2的收缩压相对于基础水平（分别为163±3和163±3 mmHg）有相似的持续升高（分别为171±3和174±2 mmHg），而CH组则没有。所有暴露组的心率均出现同等程度的持续下降（343±14次/分钟）。慢性间歇性低氧暴露导致轻度红细胞增多症和心率下降。低氧的影响在暴露的第一个月就已明显，在第三个月达到更明显的表现并趋于稳定。
