title: Placentation in the alpaca Lama pacos.
abstract: Reproduction in South American camelids is poorly studied. To extend our knowledge of the development and cellular physiology of the placenta in the alpaca Lama pacos, we have examined specimens from day 150 of pregnancy to term. Morphological investigations using light, transmission and scanning electron microscopy, the histochemical localization of iron, alkaline and acid phosphatase activity, and the immunodetection of placental lactogen hormone were performed. Throughout pregnancy there was a progressive increase in the depths of folds on the uterine mucosa surface together with a thickening of the endometrium. Glandular cells exhibited PAS and acid phosphatase (AcP) positive secretion granules. In the chorion, giant trophoblast polyploid cells gradually became more numerous and larger. Non-giant cells exhibited positive granules for PAS, alkaline phosphatase (AkP) reaction and immunostaining for bovine placental lactogen hormone (PLH). SDS -PAGE electrophoresis and Western blotting procedures also confirmed the presence of a bovine PLH-like glycoprotein in the fetal alpaca placenta. Over the glandular openings, the chorion formed typical areolae, where the trophoblast exhibited AcP and PAS positive reactions. At these sites, the fetal endothelial cells contained iron-storage granules in their cytoplasm. The trophoblast-epithelial interface exhibited a complex microvillous interdigitation, in which an AkP reaction was very prominent. The chorionic capillaries progressively indented adjacent trophoblast cells. These data suggest that although the epitheliochorial alpaca placenta is diffuse, various trophoblast cell types and specialized areas of the maternofetal interface give the placenta micro-regional functions where histiotrophic nutrition, hormone production and molecular exchange are prevalent.
authors.affiliation: Faculty of Veterinary Medicine & Zootechnology, National University Altiplano, 291 Puno, Casilla, Peru.
authors.forename: Luis
authors.initials: L
authors.lastname: Olivera
authors.forename: Douglas
authors.initials: D
authors.lastname: Zago
authors.forename: Rudolf
authors.initials: R
authors.lastname: Leiser
authors.forename: Carolyn
authors.initials: C
authors.lastname: Jones
authors.forename: Estela
authors.initials: E
authors.lastname: Bevilacqua
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002161:Camelids, New World / Q000033:anatomy & histology* / Q000378:metabolism; D002196:Capillaries / Q000378:metabolism / Q000648:ultrastructure; D048429:Cell Size / Q000502:physiology; D002823:Chorion / Q000098:blood supply / Q000378:metabolism / Q000648:ultrastructure; D004717:Endometrium / Q000378:metabolism / Q000648:ultrastructure; D004847:Epithelial Cells / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D007150:Immunohistochemistry; D008791:Metrial Gland / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008871:Microvilli / Q000378:metabolism / Q000648:ultrastructure; D010920:Placenta / Q000378:metabolism / Q000648:ultrastructure*; D010928:Placental Lactogen / Q000378:metabolism; D010929:Placentation; D011247:Pregnancy / Q000502:physiology*; D014327:Trophoblasts / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D010928:Placental Lactogen; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase