Butyrolactone I reversibly alters nuclear configuration, periooplasmic microtubules and development of porcine oocytes
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Proteolytically Degraded Alginate Hydrogels and Hydrophobic Microbioreactors for Porcine Oocyte Encapsulation
Published on: July 30, 2020
Ya-Chi Weng1, Shi-Wen Sha, Chii-Ming Chiou
1Department of Animal Science, National Chia-Yi University, Chia-Yi 600, Taiwan, ROC.
Abstract:
In the present study, we investigated the effects of specific cdc2 kinase inhibitor, butyrolactone I (BL I) on the prevention of germinal vesicle breakdown, changes of microtubular structures, and development of porcine oocytes after removal of the drug. In Experiment 1, cumulus-oocyte complexes (COCs) were cultured (44 h) in NCSU-23 medium containing different concentrations of BL I. The percentages of oocytes remaining at GV stage were 0, 0, 32, 80, and 84% (P<0.05), and the maturation rates were 86, 63, 30, 0, and 0% (P<0.05) for oocytes treated with 0, 10, 20, 40, and 80 microM of BL I, respectively. When oocytes were released from BL I incubation (Experiment 2) and cultured for an additional 44 h, 79, 84, and 83% of oocytes resumed meiosis, but only 52, 38 and 17% of oocytes reached normal metaphase II (MII) stage in the groups treated with 20, 40 and 80 microM BL I, respectively. In Experiments 3-5, reversibility and development of oocytes and embryos were evaluated after removal of the inhibitor. A reduced duration of BL I incubation (22 h) at 20 microM increased the percentage of oocytes remaining at the GV stage compared to the control group (85% versus 9%, P<0.05). Blastocyst rates were lower in treatment groups than in the control (44 h) group (0-14% versus 24%; P<0.05). However, all developing blastocysts possessed similar cell numbers, regardless of the drug-treated or non-treated controls. Taken together, treatment with 20-80 microM of BL I effectively prevented the resumption of meiosis and polymerization of periooplasmic microtubules. Furthermore, reversibility of the oocytes after reduced duration of BL I treatment was satisfactory.
Insights
Butyrolactone I (BL I) effectively prevents germinal vesicle breakdown in porcine oocytes. Reversibility was observed after reduced exposure, though blastocyst rates were impacted.
Area of Science:
- Reproductive Biology
- Cell Biology
- Developmental Biology
Background:
- Meiosis resumption and microtubule organization are critical for oocyte maturation.
- cdc2 kinase activity regulates these processes.
- Butyrolactone I (BL I) is a specific cdc2 kinase inhibitor.
Purpose of the Study:
- To investigate the effects of BL I on porcine oocyte maturation.
- To assess the prevention of germinal vesicle breakdown (GVBD).
- To evaluate changes in microtubular structures and oocyte/embryo development after drug removal.
Main Methods:
- Porcine oocytes (cumulus-oocyte complexes) were cultured with varying BL I concentrations (0-80 microM).
- Oocytes were released from BL I and cultured further to assess maturation and development.
- Reversibility and embryo development were evaluated after reduced BL I incubation periods.
Main Results:
- BL I (20-80 microM) significantly inhibited GVBD and oocyte maturation.
- Reduced exposure to BL I allowed meiosis resumption, but MII stage attainment was compromised.
- Blastocyst formation rates were lower in BL I treated groups, but blastocyst cell numbers were comparable.
Conclusions:
- BL I effectively inhibits meiosis resumption and microtubule polymerization in porcine oocytes.
- Satisfactory reversibility was achieved after reduced BL I treatment duration.
- BL I shows potential for controlling oocyte maturation, but impacts subsequent development.
