Lipid droplets in clusters negatively affect Bos indicus embryos during cryopreservation |
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| Authors: | Eva Patricia López‐Damián José Alfredo Jiménez‐Medina Miguel Angel Lammoglia Jaime Arturo Pimentel Lourdes Teresa Agredano‐Moreno Chris Wood Carlos Salvador Galina Tatiana Fiordelisio |
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| Institution: | 1. Facultad de Ciencias, Departamento de Ecología y Recursos Naturales, Biología, Laboratorio de Neuroendocrinología Comparada, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, México;2. Facultad de Ciencias Biológicas y Agropecuarias, Universidad Veracruzana, Tuxpan, México;3. Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México;4. Facultad de Ciencias, Departamento de Biología Celular, Laboratorio de Microscopía Electrónica, Edificio Tlahuizcalpan y Laboratorio de Nanobiología Celular, Universidad Nacional Autónoma de México, México, México;5. Departamento de Reproducción Animal, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, México |
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| Abstract: | Embryo transfer using cryopreserved B. indicus embryos results in low pregnancy rates. The low viability of B. indicus embryos is likely a result of their low freezability relative to embryos from other species, notably B. taurus. Freezability is probably related to the quantity of lipid droplets in the embryonic cells. However, the mechanism underlying this association is unknown. Using multiphoton and transmission electron microscopy, the proportion, volume, morphology and composition of lipid droplets in fresh and cryopreserved B. indicus and B. taurus embryos were studied. B. indicus embryos have more droplets than B. taurus and a greater percentage of lipid droplets in clusters (34% vs. 24%; p < 0.05). Also, B. indicus individual droplets are of greater volume than those of B. taurus (47 μm3 vs. 34 μm3; p < 0.05). After freezing, the percentage of clusters decreased in B. indicus (11% vs. 5%; p < 0.05), while in B. taurus they increased (2% vs. 7%; p < 0.05). Freezing influenced the lipid droplet morphology, increasing the number of cracked droplets in B. indicus embryos (33% fresh vs. 62% frozen; p < 0.05), but not in B. taurus embryos (35% fresh vs. 34% frozen; ns). Regarding composition, saturated lipid droplets prevail in B. indicus embryos, contrary to B. taurus embryos. We observed differences in lipid droplet organization, proportion, volume, morphology and composition between B. indicus and B. taurus embryos which are altered in opposite directions following freezing. |
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| Keywords: |
B indicus
B taurus
clusters embryos lipid droplets slow freezing |
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