title: Pathway for the movement of water and cryoprotectants in bovine oocytes and embryos.
abstract: The permeability of cells is important for cryopreservation. Previously, we showed in mice that the permeability to water and cryoprotectants of oocytes and embryos at early cleavage stages (early embryos) is low because these molecules move across the plasma membrane predominantly by simple diffusion through the lipid bilayer, whereas permeability of morulae and blastocysts is high because of a water channel, aquaporin 3 (AQP3). In this study, we examined the pathways for the movement of water and cryoprotectants in bovine oocytes/embryos and the role of AQP3 in the movement by determining permeability, first in intact bovine oocytes/embryos, then in bovine morulae with suppressed AQP3 expression, and finally in mouse oocytes expressing bovine AQP3. Results suggest that water moves through bovine oocytes and early embryos slowly by simple diffusion, as is the case in mice, although channel processes are also involved in the movement. On the other hand, water appears to move through morulae and blastocysts predominantly by facilitated diffusion via channels, as in mice. Like water, cryoprotectants appear to move through bovine oocytes/early embryos mostly by simple diffusion, but channel processes could also be involved in the movement of glycerol and ethylene glycol, unlike that in mice. In bovine morulae, although glycerol and ethylene glycol would move predominantly by facilitated diffusion, mostly through AQP3, as in mice, dimethylsulfoxide appears to move predominantly by simple diffusion, unlike in mice. These results indicate that permeability-related properties of bovine oocytes/embryos are similar to those of mouse oocytes/embryos, but species-specific differences do exist.
authors.affiliation: Laboratory of Animal Science, College of Agriculture, Kochi University, Nankoku, Japan.
authors.forename: Bo
authors.initials: B
authors.lastname: Jin
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Kawai
authors.forename: Takao
authors.initials: T
authors.lastname: Hara
authors.forename: Shoko
authors.initials: S
authors.lastname: Takeda
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Seki
authors.forename: Yu-Ichi
authors.initials: Y
authors.lastname: Nakata
authors.forename: Kazutsugu
authors.initials: K
authors.lastname: Matsukawa
authors.forename: Chihiro
authors.initials: C
authors.lastname: Koshimoto
authors.forename: Magosaburo
authors.initials: M
authors.lastname: Kasai
authors.forename: Keisuke
authors.initials: K
authors.lastname: Edashige
mesh_terms: D000818:Animals; D051400:Aquaporin 3 / Q000235:genetics / Q000378:metabolism*; D001755:Blastocyst / Q000187:drug effects / Q000378:metabolism; D002417:Cattle; D048429:Cell Size / Q000187:drug effects*; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D004058:Diffusion / Q000187:drug effects; D004477:Ectogenesis; D055459:Facilitated Diffusion / Q000187:drug effects; D005307:Fertilization in Vitro; D018495:Fluid Shifts / Q000187:drug effects*; D020868:Gene Silencing; D006982:Hypertonic Solutions; D059471:In Vitro Oocyte Maturation Techniques; D051379:Mice; D008813:Mice, Inbred ICR; D009028:Morula / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D010539:Permeability / Q000187:drug effects; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity
chemical_list: D003451:Cryoprotective Agents; D006982:Hypertonic Solutions; D011994:Recombinant Proteins; D051400:Aquaporin 3