Placenta of an antarctic fur seal, Arctocephalus gazella (Peters, 1875) after spontaneous abortion

GIMENA GOMEZ CASTRO ; ROCÍO HERNÁNDEZ ; CLEOPATRA M. LOZA ; JUAN P. LOUREIRO; MARIANA A. WOUDWYK ; MARIANO SCIANDA ; SERGIO RODRÍGUEZ HEREDIA ; VANESA B. TRAVERSO ; CLAUDIO G. BARBEITO ; MÓNICA E. DIESSLER

Bogota

Simposio; IX SLIMP-Latin American Society for Materno Fetal Interaction and Placenta virtual meeting; 2022

Gimena Gomez Castro 1-2, Rocío Hernández 1-2, Cleopatra M. Loza 1-3, Juan P. Loureiro 4-5, Mariana A. Woudwyk 1, Mariano Scianda 1, Sergio Rodríguez Heredia 5, Vanesa B. Traverso 5, Claudio G. Barbeito 1-2, Mónica E. Diessler 1.1-Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada (LHYEDEC), Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata (FCV, UNLP), La Plata. Argentina; 2-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). FCV, UNLP, La Plata. Argentina; 3- Morphos, Laboratorio de Morfología Evolutiva y de Desarrollo (CONICET), Facultad de Ciencias Naturales y Museo, UNLP, La Plata, Argentina; 4- Catedra de Anatomía Descriptiva, FCV, UNLP; 5- Fundación Mundo Marino, San Clemente del Tuyú, Buenos Aires, Argentina.TitlePlacenta of an antarctic fur seal, Arctocephalus gazella (Peters, 1875) after spontaneous abortion Objective The aim of the work was to describe the placental morphology of an antarctic fur seal (Pinnipedia, Otariidae, Arctocephalinae) which underwent spontaneous abortion after 9-months gestation. MethodologyA wild born female was found stranded in La Plata River. It was rescued, brought to the Mundo Marino oceanarium for rehabilitation, and aborted shortly afterwards. The placenta was formalin-fixed in situ and transferred to the LHYEDEC where it was photographed, described, and processed by histological techniques.ResultsThe chorionic sac was sausage-shaped and measured 38 cm in greatest length. The zonary placenta was constituted by a belt-shaped band; it was uneven in width (at the antimesometrial aspect it was 14.4 cm whereas at the mesometrial aspect it was only 8 cm) and quite uniform in thick, measuring 1-1.2 cm. The external surface was rough; orange margins could be seen. The chorioallantoic membrane was smooth and semi-transparent, thereby allowing several scattered orange areas to show through. No macroscopic lesions were noticed. Microscopically, the organ was arranged in poor delimited lobules, composed of maternal and fetal structures with labyrinthine arrangement, forming an endotheliochorial barrier. Mesenchymal axes of the chorionic villi were regularly parallel. Labyrinthine trophoblast constituted a thin layer surrounding the interstitial membrane of maternal vessels; very few cells in this zone could be discerned as discrete cytotrophoblast cells. There were zones of extralabyrinthine chorionic villi lined by columnar trophoblastic epithelium with phagocytic aspect. In the maternal zone, scattered areas of slightly edematous connective tissue (with moderately abundant leucocytes), some eroded vessels and pooled blood were noticed. Conclusion In terms of its anatomical and histological general features, this zonary placenta matches those of other pinniped´s. Maternal large ?sinusoidal? vessels, described in term placentas of other pinnipeds, were not observed here. As far as we know, this is the first description of the organ in the Arctocephalus genus.