高海拔环境中的生育能力受到黄体功能障碍的影响：缺氧和氧化应激的相对作用。
Fertility in a high-altitude environment is compromised by luteal dysfunction: the relative roles of hypoxia and oxidative stress.
机构信息
Faculty of Veterinary Sciences, University of Chile, Casilla 2, Correo 15, La Granja, Santiago, Chile.
出版信息
Reprod Biol Endocrinol. 2013 Mar 23;11:24. doi: 10.1186/1477-7827-11-24.
BACKGROUND
At high altitudes, hypoxia, oxidative stress or both compromise sheep fertility. In the present work, we tested the relative effect of short- or long-term exposure to high altitude hypobaric hypoxia and oxidative stress on corpora luteal structure and function.
METHODS
The growth dynamics of the corpora lutea during the estrous cycle were studied daily by ultrasonography in cycling sheep that were either native or naïve to high-altitude conditions and that were supplemented or not supplemented with antioxidant vitamins. Arterial and venous blood samples were simultaneously drawn for determination of gases and oxidative stress biomarkers and progesterone measurement. On day five after ovulation in the next cycle, the ovaries were removed for immunodetection of luteal HIF-1alpha and VEGF and IGF-I and to detect IGF-II gene expression.
RESULTS
The results showed that both short- and long-term exposure to high-altitude conditions decreased luteal growth and IGF-I and IGF-II gene expression but increased HIF-1 alpha and VEGF immunoexpression. The level of plasma progesterone was also increased at a high altitude, although an association with increased corpus luteum vascularization was only found in sheep native to a high-altitude location. Administration of antioxidant vitamins resulted in a limited effect, which was restricted to decreased expression of oxidative stress biomarkers and luteal HIF-1alpha and VEGF immunoexpression.
CONCLUSIONS
Exposure of the sheep to high-altitude hypobaric hypoxia for short or long time periods affects the development and function of the corpus luteum. Moreover, the observed association of oxidative stress with hypoxia and the absence of any significant effect of antioxidant vitamins on most anatomical and functional corpus luteum traits suggests that the effects of high altitude on this ovarian structure are mainly mediated by hypoxia. Thus, these findings may help explain the decrease in sheep fertility at a high altitude.
背景
在高海拔地区，缺氧、氧化应激或两者都会损害绵羊的生育能力。在本工作中，我们测试了短期或长期暴露于高海拔低氧和氧化应激对黄体结构和功能的相对影响。
方法
通过超声检查，对适应或不适应高海拔环境的循环绵羊发情周期中黄体的生长动态进行每日研究，并补充或不补充抗氧化维生素。同时采集动脉和静脉血样，以测定气体和氧化应激生物标志物及孕酮。在下一个周期排卵后第五天，切除卵巢，以检测黄体 HIF-1alpha 和 VEGF 及 IGF-I 的免疫表达，并检测 IGF-II 基因表达。
结果
结果表明，短期和长期暴露于高海拔环境均降低黄体生长和 IGF-I 和 IGF-II 基因表达，但增加 HIF-1alpha 和 VEGF 免疫表达。尽管仅在适应高海拔环境的绵羊中发现黄体血管化增加与血浆孕酮水平升高相关，但在高海拔环境中，孕酮水平也升高。抗氧化维生素的给予仅产生有限的效果，仅限于降低氧化应激生物标志物和黄体 HIF-1alpha 和 VEGF 免疫表达。
结论
绵羊短期或长期暴露于高海拔低氧环境会影响黄体的发育和功能。此外，观察到氧化应激与缺氧相关，以及抗氧化维生素对大多数黄体解剖和功能特征没有明显影响，提示高海拔对这种卵巢结构的影响主要是通过缺氧介导的。因此，这些发现可能有助于解释绵羊在高海拔地区生育能力下降的原因。
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