Increasing culture time from 48 to 96 or 144 hours increases the proportions of equine cumulus oocyte complexes with negative or fragmented nucleus morphology.
Abstract: The objective was to test the hypothesis that increasing equine oocyte culture time from 48 to 96 or 144 h increases nucleus maturation of equine oocytes. The hypothesis was not supported because condensed chromatin-stage oocytes decreased (P<0.01) from 33/126 (26.2%) at 48 h or 34/95 (35.8%) at 96 h to 11/117 (9.4%) at 144 h, and polar body-stage oocytes decreased (P<0.01) from 65/126 (51.6%) at 48 h to 25/95 (26.3%) at 96 h and (P<0.01) to 1/117 (0.9%) at 144 h. Negative (non-staining) oocytes increased (P<0.01) from 16/126 (12.7%) at 48 h or 15/95 (15.8%) at 96 h to 39/117 (33.3%) at 144 h. Fragmented oocytes (with and without fluorescent areas) increased (P<0.01) from 4/126 (3.2%) at 48 h to 20/95 (21.1%) at 96 h and increased again to 60/117 (51.3%) at 144 h. When fragmented oocytes having 1 fluorescent area were defined as condensed chromatin-stage and fragmented oocytes having 2 fluorescent areas were defined as polar body-stage, condensed chromatin-stage oocytes increased (P < 0.05) from 34/126 (27.0%) at 48 h to 38/95 (40.0%) at 96 h, but decreased (P<0.05) to 19/117 (16.2%) at 144 h. Polar body-stage oocytes decreased (P<0.01) from 66/126 (52.4%) at 48 h to 27/95 (28.4%) at 96 h and decreased again to 7/117 (6.0%) at 144 h. Fragmented oocytes without any fluorescent areas increased (P<0.01) from 2/126 (1.6%) at 48 h to 14/95 (14.7%) at 96 h and increased again to 46/117 (39.3%) at 144 h. Under the conditions of this experiment, the hypothesis that increasing the culture time of equine oocytes from 48 to 96 or 144 h would increase oocyte maturation was not supported. We propose that the culture system needs to be improved before this hypothesis can be adequately tested, because prolonged culture significantly increased the proportions of negative and fragmented equine oocytes.
Publication Date: 2001-05-17 PubMed ID: 11354713DOI: 10.1016/s0093-691x(01)00501-5Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study evaluates the impact of extended culture times on horse oocyte maturation, demonstrating that contrary to the initial hypothesis, lengthier culture periods led to a higher proportion of negatively staining or fragmented oocytes.
Objective and Hypothesis
- The objective of the study was to determine if extended culture times, specifically comparing 48, 96, and 144 hours, would lead to improved nuclear maturation in horse oocytes, the cells that develop into eggs.
- The researchers hypothesized that longer culture times would result in this improved oocyte maturation, marking a potential advancement in horse reproductive techniques.
Methodology and Results
- The team tested their hypothesis by cultivating horse oocytes for 48, 96, and 144 hour periods, observing changes in maturity.
- Results showed a decrease in the number of oocytes at the condensed chromatin stage and the polar body stage as the culture time increased. These stages are indicative of progressing oocyte maturation.
- On the other hand, the number of negatively staining or non-viable (negative) oocytes, and fragmented oocytes increased with longer culture times. This indicated a decrease in oocyte health and maturation, opposite to the study’s hypothesis.
- When the team reclassified certain fragmented oocytes as condensed chromatin-stage or polar body-stage oocytes based on the presence of fluorescent areas, the same trend remained — an increase in culture time led to fewer mature and more damaged or non-viable oocytes.
Conclusion and Future Directions
- The study did not support the initial hypothesis: extending the culture time of horse oocytes didn’t improve their maturation but increased the proportions of negative and fragmented oocytes, which are unhealthy or non-viable.
- Suggestions for future research include finding ways to improve the culture system to better support oocyte maturation over longer periods, emphasizing the complexity of cell-culture techniques and the challenge of maintaining cell viability over extended periods.
Cite This Article
APA
Gable TL, Woods GL.
(2001).
Increasing culture time from 48 to 96 or 144 hours increases the proportions of equine cumulus oocyte complexes with negative or fragmented nucleus morphology.
Theriogenology, 55(7), 1549-1560.
https://doi.org/10.1016/s0093-691x(01)00501-5 Publication
Researcher Affiliations
- Department of Animal and Veterinary Science, University of Idaho, Moscow 83844-2201, USA.
MeSH Terms
- Animals
- Cell Culture Techniques
- Cell Nucleus / ultrastructure
- Chromatin / ultrastructure
- Culture Media
- Cytoplasm / ultrastructure
- Female
- Follicular Fluid
- Horses
- Microscopy, Confocal
- Oocytes / physiology
- Oocytes / ultrastructure
- Ovarian Follicle / cytology
- Ovarian Follicle / physiology
- Time Factors
Citations
This article has been cited 2 times.- Jiao Y, Wang Y, Jiang T, Wen K, Cong P, Chen Y, He Z. Quercetin protects porcine oocytes from in vitro aging by reducing oxidative stress and maintaining the mitochondrial functions.. Front Cell Dev Biol 2022;10:915898.
- Zhao MH, Jin YX, Lee SK, Kim NH, Cui XS. Artificial control maturation of porcine oocyte by dibutyryl cyclicAMP.. Anim Cells Syst (Seoul) 2014 Feb;18(1):52-58.
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