Fertility in a high-altitude environment is compromised by luteal dysfunction: the relative roles of hypoxia and oxidative stress

Reproductive Biology and Endocrinology

Research

Laura Torres-Rovira¹  Antonio González-Bulnes²  Susana Astiz²  Giorgio Castellaro³  Bessie Urquieta⁴  Laura Pérez⁴  Mónica De los Reyes⁴  Víctor H Parraguez⁵  Adriana Aguado-Martínez⁶ 

[1] Department of Animal Biology, University of Sassari, Via Vienna 2, 07100, Sassari, Italy;Department of Animal Reproduction, INIA, Av. Puerta de Hierro s/n, 28040, Madrid, Spain;Faculty of Agricultural Sciences, University of Chile, Casilla 2, Correo 15, La Granja, Santiago, Chile;Faculty of Veterinary Sciences, University of Chile, Casilla 2, Correo 15, La Granja, Santiago, Chile;Faculty of Veterinary Sciences, University of Chile, Casilla 2, Correo 15, La Granja, Santiago, Chile;Faculty of Agricultural Sciences, University of Chile, Casilla 2, Correo 15, La Granja, Santiago, Chile;International Centre for Andean Studies, University of Chile, Casilla 2, Correo 15Santiago, La Granja, Chile;SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain;

关键词: Sheep;    Corpus luteum function;    Hypoxia;    Oxidative stress;    Antioxidant vitamins;   

DOI  :  10.1186/1477-7827-11-24

 received in 2012-12-27, accepted in 2013-03-13,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundAt 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.MethodsThe 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.ResultsThe 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.ConclusionsExposure 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.

【 授权许可】

CC BY   
© Parraguez et al.; licensee BioMed Central Ltd. 2013