Ou L C, Smith R P
Proc Soc Exp Biol Med. 1984 Nov;177(2):308-11. doi: 10.3181/00379727-177-41948.
On chronic exposure to hypoxia, the commercially available Hilltop (H) strain of male Sprague-Dawley rats develops severe pulmonary hypertension, right ventricular hypertrophy (RVH), and polycythemia. These signs of chronic mountain sickness are associated with a high mortality rate. In contrast, the Madison (M) strain of Sprague-Dawley rats remains healthy with significantly less severe cardiopulmonary and hematological responses. Breeding experiments under locally controlled conditions were undertaken to determine if the differences between the two strains were genetically determined and to look for possible sex differences. Following 30 to 50 days exposure to a simulated altitude of 18,000 ft, the first generation of male H rats exhibited a higher right ventricular peak systolic pressure (RVPP), a more pronounced RVH, and a greater degree of polycythemia than the male M rats. The H rats had a mortality rate of 40% in contrast to a rate of 0% in the male M rats. The first generation of female H rats also developed a higher RVPP, a greater RVH, and more severe polycythemia than that in the female M rats. There were no differences in RVPP or RVH between the males and females of either strain. Females of both strains tolerated the hypoxic exposure with a 0% mortality rate. The data suggest that the differences between the males of H and M strains in their cardiopulmonary and hematological responses and in their susceptibilities to chronic hypoxia are genetic in nature. They further suggest that the female resistance to hypoxia is not due to milder cardiopulmonary responses. Perhaps female rats tolerate RVH better than male rats, at least of the H strain.
长期暴露于低氧环境下，市售的雄性斯普拉格 - 道利大鼠Hilltop（H）品系会出现严重的肺动脉高压、右心室肥大（RVH）和红细胞增多症。这些慢性高山病的症状与高死亡率相关。相比之下，斯普拉格 - 道利大鼠的Madison（M）品系保持健康，心肺和血液学反应明显较轻。在当地可控条件下进行了繁殖实验，以确定这两个品系之间的差异是否由基因决定，并寻找可能的性别差异。在暴露于模拟海拔18,000英尺30至50天后，第一代雄性H大鼠比雄性M大鼠表现出更高的右心室收缩压峰值（RVPP）、更明显的RVH和更高程度的红细胞增多症。H大鼠的死亡率为40%，而雄性M大鼠的死亡率为0%。第一代雌性H大鼠也比雌性M大鼠表现出更高的RVPP、更大程度的RVH和更严重的红细胞增多症。两个品系的雄性和雌性在RVPP或RVH方面没有差异。两个品系的雌性在低氧暴露下的死亡率均为0%。数据表明，H和M品系雄性在心肺和血液学反应以及对慢性低氧的易感性方面的差异本质上是由基因决定的。数据还进一步表明，雌性对低氧的抵抗力并非源于较轻的心肺反应。也许雌性大鼠比雄性大鼠更能耐受RVH，至少对于H品系是这样。
