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The Influence of Oxygen Tension on Cumulus Cell Viability of Canine COCs Matured in High‐Glucose Medium
Author(s) -
Silva AEF,
Rodriguez P,
Cavalcante LF,
Rodrigues BA,
Rodrigues JL
Publication year - 2009
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/j.1439-0531.2009.01406.x
Subject(s) - oxygen tension , oxygen , viability assay , andrology , chemistry , cell , biology , medicine , biochemistry , organic chemistry
Contents High in vitro oxygen (O 2 ) tensions are associated with enhanced levels of reactive oxygen species and cumulus oocyte complex (COC) apoptosis. The objective of this study was to determine the influence of O 2 tension on cumulus cell (CC) viability from canine oocytes. Cumulus oocyte complexes were distributed into three groups (CG, T20 and T5) and two O 2 tension levels (20% and 5%). The control group (CG) was matured in vitro in a humidified atmosphere with 5% CO 2 in air in TCM199 with 26.19 m m sodium bicarbonate, 10% (v/v) foetal calf serum (FCS), 0.10 m m gentamicin, 0.20 m m pyruvic acid, 20 μg/ml oestradiol, 0.5 μg/ml follicle‐stimulating hormone, 0.03 IU/ml human chorionic gonadotropin, and 1.0 μg/ml human somatotropin. Groups T20 and T5 were matured under 20% or 5% O 2 tensions respectively in a high‐glucose medium, without FCS. T20 and T5 were as CG, and supplemented with 0.1% Polyvinyl Alcohol, and 5.5 m m glucose. After 48 h of IVM, CCs from COCs were stained with propidium iodide (1.50 m m ). The results showed that viability of CCs (cytoplasmic features and nuclear morphological integrity) was different for the three groups. Rates of apoptosis were at 57.9% (521/900) for CG, 54.4% (490/900) for T20 and 38.9% (350/900) for T5 (p < 0.001). Predominant features in apoptotic cells (n = 1361) were DNA nuclear fragments (94.0%). It was concluded that CCs of canine COCs cultured in high‐glucose medium showed significantly less apoptosis than those cultured in medium with FCS. Low O 2 tension was efficient in reducing apoptosis in canine CCs.