APICHELA Silvana Andrea
congresos y reuniones científicas
Libro de Resúmenes
Simposio; Simposium Internacional de Investigaciones sobre Camelidos Sudamericanos y Seminario Final del Proyecto DECAMA; 2006
Institución organizadora:
DECAMA, Programa nacional de camélidos sudamericanos, Desco, Ente per le nuove tecnologie lénergia e lámbiente, Univ. Católica de Santa María, Univ. Católica de Córdoba
The oviduct is involved in the sperm capacitation, fertilization and early development. Because that in South American Camelid (SAC) the ovulation occurs approximately 36 hs after mating, it is possible that the sperm - oviduct interaction (necessary to maintain the sperm viability until fertilization) could be different from that of mammals in which ovulation occurs approximately at the same time of mating. This reproductive feature turns the SAC oviduct in an adequate biological system for studying the beneficial effect of the oviduct on the sperm. Our goal is to know if the SACs oviduct participates actively whether retarding capacitation or maintaining the sperm viability and motility, in order to maintain the sperm fertility capability until ovulation. By perfusion of alpaca oviduct of mated females, it was reported that utero tubal junction (UTJ) contain the main percentage of free sperm. In guanaco, the presence of spermatozoa in the isthmus until 120 hs after mating also was reported. However there are not references about any type of interaction between sperm and oviductal cells in SAC. In bovine, the sperm binds to the oviduct epithelial cells (OEC). Apparently these cells have the capacity to delay the aging of the sperm by avoiding the capacitation. In vitro studies showed sperm bind to the OEC in cows, human, hamster, heifer, pig and mice. The molecules involved in such binding are still unknown. Nevertheless it is known that carbohydrates recognition mechanisms are involved in this apparently specific recognitions. In this study the oviducts were obtained 24 hs post mating from adult lama females of the National Institute of Farming Technology site in Abra Pampa (Jujuy, Argentina which showing an mature dominant follicle ovary. Non mated females in the same follicular phase were utilized as control. UTJ and isthmus of the ipsilateral oviduct were dissected and processed for transmission (TEM) and for scanning electron microscopy (SEM). MET microphotographs of the oviduct revealed pseudo stratified epithelium and show two cell types: ciliated and secretory cells. The abundance of ciliated cells increases from the UTJ to the isthmus, while secretory cells are more abundant in the UTJ. Ciliated cells have a central spherical nucleus and numerous cilia anchored to the terminal network. No cilia degeneration was observed. The secretory cells of both segments possess microvilli and contain abundant secretion granules. The cell of UTJ presents small dense granules while in the isthmus cells the granules show heterogeneous electron density and larger size than UTJ granules. In both cases, the granules are located in the apical cytoplasm, where spherical mitochondria can also be observed. Apparently the secretion product is eliminated with loss of the apical cytoplasm as occur in the oviduct of other animals. The morphology of the epithelium changed when secretion products are released being observed a decrease of the epithelial height and an increase of the microvilly length. By SEM the spermatozoa were observed only in the UUT, immersed in a substance that shows at TEM low electron density. Interestingly this substance is absent in non-mated females indicating a possible seminal origin. In some case sperm show non-specifically adhesion by its heads to both cell types.