TY - JOUR
T1 - Ovine placenta at high altitudes
T2 - Comparison of animals with different times of adaptation to hypoxic environment
AU - Parraguez, Víctor H.
AU - Atlagich, Miljenko
AU - Díaz, Rodrigo
AU - Cepeda, Raquel
AU - González, Carlos
AU - De los Reyes, Mónica
AU - Bruzzone, María E.
AU - Behn, Claus
AU - Raggi, Luis A.
N1 - Funding Information:
We thank Dr. Valeria Rojas for statistical support, Dr. Bessie Urquieta for the revision of the manuscript, and Mr. Gabino Llusco for his assistance with animal care. This work was totally supported by FONDECYT Grant No. 1020706, from CONICYT, Chile.
PY - 2006/9
Y1 - 2006/9
N2 - Fetal growth and newborn weight from ovine gestations at high altitudes (HA) are greater in ewes that live at HA for several generations than in those native to low altitudes (LA) exposed to HA only during pregnancy. Because the placenta is a key regulator of fetal growth, the present study compared placental characteristics in term pregnancies among ewes native to HA and LA. Conception occurred at HA and ewes continued to reside at HA throughout pregnancy or conception occurred at LA and ewes were transported to HA or remained at LA (controls). Ewes native to LA were moved to HA shortly after mating (group LH) and joined with pregnant ewes native to HA (group HH). After parturition, placental cotyledons were counted and measured for total area and histological estimation of surface occupied by vasculature. The total surface of the cotyledons and surface occupied by vasculature were greater at HA, whereas the number of cotyledons was smaller at HA. These changes were more pronounced in ewes of the HH compared with the LH group. The present study showed that exposure to HA induces, in pregnant ewes, placental morphological changes that may improve maternal-fetal exchange. Moreover, because of accentuation of placental changes in ewes with long-term residence at HA, this appears to be an efficient mechanism of adaptation to hypobaric hypoxia.
AB - Fetal growth and newborn weight from ovine gestations at high altitudes (HA) are greater in ewes that live at HA for several generations than in those native to low altitudes (LA) exposed to HA only during pregnancy. Because the placenta is a key regulator of fetal growth, the present study compared placental characteristics in term pregnancies among ewes native to HA and LA. Conception occurred at HA and ewes continued to reside at HA throughout pregnancy or conception occurred at LA and ewes were transported to HA or remained at LA (controls). Ewes native to LA were moved to HA shortly after mating (group LH) and joined with pregnant ewes native to HA (group HH). After parturition, placental cotyledons were counted and measured for total area and histological estimation of surface occupied by vasculature. The total surface of the cotyledons and surface occupied by vasculature were greater at HA, whereas the number of cotyledons was smaller at HA. These changes were more pronounced in ewes of the HH compared with the LH group. The present study showed that exposure to HA induces, in pregnant ewes, placental morphological changes that may improve maternal-fetal exchange. Moreover, because of accentuation of placental changes in ewes with long-term residence at HA, this appears to be an efficient mechanism of adaptation to hypobaric hypoxia.
KW - High altitude
KW - Sheep-placenta
UR - http://www.scopus.com/inward/record.url?scp=33645296876&partnerID=8YFLogxK
U2 - 10.1016/j.anireprosci.2005.11.003
DO - 10.1016/j.anireprosci.2005.11.003
M3 - Article
C2 - 16337102
AN - SCOPUS:33645296876
SN - 0378-4320
VL - 95
SP - 151
EP - 157
JO - Animal Reproduction Science
JF - Animal Reproduction Science
IS - 1-2
ER -