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Nuclear maturation of canine oocytes cultured in protein‐free media
Author(s) -
Songsasen N.,
Yu I.,
Leibo S.P.
Publication year - 2002
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.10130
Subject(s) - biology , microbiology and biotechnology , oocyte , nuclear protein , andrology , computational biology , embryo , genetics , gene , transcription factor , medicine
The objective of this study was to determine the ability of canine oocytes to complete nuclear maturation in a protein‐free medium. Oocytes obtained from ovaries of bitches aged 6 months to 2 years were cultured either in TCM199 or CMRL1066 medium without protein supplementation in 5% or 20% O 2 . Sixteen of 121 (13%) oocytes cultured in TCM199 reached metaphase II, but only 1 of 135 oocytes cultured in CMRL1066 did so ( P < 0.05). Oxygen concentration did not affect nuclear maturation. An additional 103 oocytes were cultured in TCM199 for 48 hr, inseminated with chilled ejaculated spermatozoa, fixed in 1:3 acetic acid–ethanol and then stained with aceto‐orcein; 34% of these oocytes were penetrated by spermatozoa. To determine developmental competence of oocytes cultured in a protein‐free medium, 85 oocytes were cultured in TCM 199 for 48 hr, inseminated and then cultured; 7 early stage embryos were produced. The effects of growth hormone, β‐mercaptoethanol (βME), luteinizing hormone (LH) and energy substrates, alone or in combination, on nuclear maturation of oocytes cultured in a protein‐free medium were also determined. Growth hormone enhanced cumulus expansion, but did not improve nuclear maturation. β‐mercaptoethanol had no effect on nuclear maturation. However, percentages of MII oocytes significantly decreased when the oocytes were cultured for 48 hr in the medium containing LH or a high concentration of glucose ( P < 0.05). In conclusion, canine oocytes are able to complete nuclear maturation in a protein‐free medium. The specific type of medium and other supplements significantly influence the meiotic maturation of canine oocytes. Mol. Reprod. Dev. 62: 407–415, 2002. © 2002 Wiley‐Liss, Inc.