1. Lipid content and G6PDH activity in relation to ooplasm morphology and oocyte maturational competence in the domestic cat model.
- Author
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Młodawska W, Maliński B, Godyń G, and Nosal B
- Subjects
- Animals, Cats, Female, In Vitro Oocyte Maturation Techniques veterinary, Cumulus Cells physiology, Cumulus Cells metabolism, Lipid Metabolism physiology, Lipid Droplets metabolism, Lipids, Oocytes physiology, Glucosephosphate Dehydrogenase metabolism
- Abstract
The aim of the study was to investigate the relationship between ooplasm morphology, lipid content, glucose-6-phosphate dehydrogenase activity (G6PDH) and maturation potential of domestic cat oocytes. Cumulus-oocyte complexes were classified according to ooplasm morphology: evenly dark (dCOC), heterogeneous/mosaic (hCOC), or light/transparent (lCOC), however only dCOCs are thought to be the best-quality, the remaining ones are usually rejected, therefore little is known about their intracellular properties. Lipid droplets (LDs) were visualized and quantified using Oil Red O. G6PDH activity was assessed before in vitro maturation (IVM), using the brilliant cresyl blue (BCB) test. IVM-control oocytes underwent IVM without BCB staining. The dCOCs and hCOCs had different patterns of LD spatial distribution, but similar amounts of lipid, although this tended towards being lower in hCOCs. Low G6PDH activity (BCB+) was observed in 74 %, 60 % and 24 % (P < 0.01) of dCOCs, hCOCs, and lCOCs, respectively. Significantly more BCB+ /oocytes than BCB-/oocytes reached the metaphase II stage in all groups. The maturation rate of BCB+ /hCOCs was higher than that of IVM/hCOC-controls (40 % v.s. 20 %, P < 0.001), and was comparable to that of BCB+ /dCOCs (54 %; P > 0.05). lCOCs were the smallest (P < 0.01), contained fewer (P < 0.01) lipids than dCOCs or hCOCs, and displayed reduced maturational potential. Overall, LD content and distribution, as well as G6PDH activity, in cat oocytes were strongly associated with ooplasm morphology and oocyte maturational competence. Deeper understanding of the intrinsic properties of oocytes with different ooplasm morphology using the domestic cat model, may be particularly important in the context of the conservation of endangered felids., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest., (Copyright © 2024 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier B.V. All rights reserved.)
- Published
- 2024
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