title: Extrusion and removal of lipid from the cytoplasm of porcine oocytes at the germinal vesicle stage: centrifugation under hypertonic conditions influences vitrification.
abstract: In the present study, we examined a novel lipid removal method, centrifugation in solutions made hypertonic by adding 0.27 M sugar. This allowed the lipid to be extruded and removed without the loss of active mitochondria or extra cytoplasm. The type of sugar influenced the proportion of oocytes that could be stratified by centrifugation. Glucose induced the highest extrusion rate of lipid droplets. After vitrification the rates of survival, germinal vesicle breakdown and metaphase II were 30, 26, and 7%, respectively, for lipid-removed GV oocytes; this was significantly higher (P<0.05) than for corresponding vitrified lipid-intact oocytes (2, 0, and 0%, respectively). These results indicated that this method is useful to remove whole lipid droplets without losing mitochondria and improves cryotolerance of porcine GV oocytes.
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan. k-hara@bios.tohoku.ac.jp
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Hara
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Abe
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kumada
authors.forename: Nobuya
authors.initials: N
authors.lastname: Aono
authors.forename: Jin
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasada
authors.forename: Eimei
authors.initials: E
authors.lastname: Sato
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D002498:Centrifugation; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary; D003593:Cytoplasm / Q000737:chemistry / Q000648:ultrastructure; D005260:Female; D005950:Glucose Solution, Hypertonic / Q000494:pharmacology*; D008055:Lipids / Q000302:isolation & purification*; D008846:Micromanipulation; D008928:Mitochondria / Q000648:ultrastructure; D009865:Oocytes / Q000737:chemistry* / Q000187:drug effects / Q000648:ultrastructure; D013552:Swine
chemical_list: D005950:Glucose Solution, Hypertonic; D008055:Lipids