title: Effect of 1,2-propanediol versus 1,2-ethanediol on subsequent oocyte maturation, spindle integrity, fertilization, and embryo development in vitro in the domestic cat.
abstract: This study assessed the impact of various cryoprotectant (CPA) exposures on nuclear and cytoplasmic maturation in the immature cat oocyte as a prerequisite to formulating a successful cryopreservation protocol. In experiment 1, immature oocytes were exposed to 0, 0.75, 1.5, or 3.0 M of 1,2-propanediol (PrOH) or 1,2-ethanediol (EG) at room temperature (25 degrees C) or 0 degrees C for 30 min. After CPA removal and in vitro maturation, percentage of oocytes reaching metaphase II (MII) was reduced after exposure to 3.0 M PrOH at 0 degrees C or 3.0 M EG at both temperatures. All CPA exposures increased MII spindle abnormalities compared to control, except 1.5 M PrOH at 25 degrees C. In experiments 2 and 3, immature oocytes were exposed to CPA conditions yielding optimal nuclear maturation that either had caused spindle damage (0.75 M PrOH, 1.5 M EG, and 3.0 M PrOH at 25 degrees C) or not (1.5 M PrOH at 25 degrees C). After maturation and insemination in vitro, oocytes were cultured for 7 days to assess treatment influence on developmental competence. CPA exposure did not affect fertilization, but the high incidence of MII spindle abnormalities resulted in a low percentage of cleaved embryos. Blastocyst formation and quality were influenced by both CPA types (EG was more detrimental than PrOH) and concentration (3.0 M was more detrimental than 1.5 M). Overall, cat oocytes appear to be highly sensitive to CPA except after exposure to 1.5 M PrOH at 25 degrees C, a treatment that still allowed approximately 60% of the oocytes to reach MII and approximately 20% to form blastocysts.
authors.affiliation: Department of Reproductive Sciences, Smithsonian's National Zoological Park, 3001 Connecticut Avenue NW, Washington, D.C. 20008, USA. comizzolip@si.edu
authors.forename: Pierre
authors.initials: P
authors.lastname: Comizzoli
authors.forename: David E
authors.initials: DE
authors.lastname: Wildt
authors.forename: Budhan S
authors.initials: BS
authors.lastname: Pukazhenthi
mesh_terms: D000818:Animals; D002415:Cats; D002467:Cell Nucleus / Q000187:drug effects; D003451:Cryoprotective Agents / Q000494:pharmacology*; D047108:Embryonic Development / Q000187:drug effects*; D019855:Ethylene Glycol / Q000494:pharmacology*; D005306:Fertilization / Q000187:drug effects; D005307:Fertilization in Vitro; D066298:In Vitro Techniques; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D019946:Propylene Glycol / Q000494:pharmacology*; D008941:Spindle Apparatus / Q000187:drug effects
chemical_list: D003451:Cryoprotective Agents; D019946:Propylene Glycol; D019855:Ethylene Glycol