Prematuration of bovine oocytes with butyrolactone I: Effects on meiosis progression, cytoskeleton, organelle distribution and embryo development

• Published in: Animal reproduction science Vol. 108; no. 1; pp. 49 - 65
• Main Authors: Adona, Paulo Roberto, Pires, Pedro Ratto Lisboa, Quetglas, Maria Daniela, Schwarz, K.R.L., Leal, Cláudia Lima Verde
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-10-2008; [Amsterdam]: Elsevier Science
• Subjects: 4-Butyrolactone - analogs & derivatives; 4-Butyrolactone - pharmacology; Animals; butyrolactone I; Cattle; Cattle - embryology; Cortical granules; cows; Cytoskeleton; Cytoskeleton - drug effects; Cytoskeleton - physiology; drug therapy; Embryo, Mammalian - drug effects; embryogenesis; Embryonic Development - drug effects; Embryonic Development - physiology; enzyme inhibition; enzyme inhibitors; Fertilization in Vitro - veterinary; in vitro studies; Maturation; maturity stage; Meiosis; Meiotic arrest; Mitochondria; oocytes; Oocytes - cytology; Oocytes - drug effects; Oocytes - growth & development; organelles; Organelles - physiology; Cytoskeleton; Mitochondria; Maturation; Cattle; Meiotic arrest; Cortical granules
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/j.anireprosci.2007.07.002

The effects of prematuration (PM) of bovine oocytes with butyrolactone I (BLI) for 24
h on meiosis progression, cell structures and embryo development were assessed. Germinal vesicle (GV) rates decreased (97.4–65.1%,
P
<
0.05) with decreasing BLI concentrations (100–25
μM). Without BSA in PM medium, GV rates were similar (98.7–97.2,
P
>
0.05) with low BLI (10–25
μM). After
in vitro maturation (IVM) for 24
h, metaphase II (MII) rates for controls (IVM only) were similar (91.1%,
P
>
0.05) to PM with 10
μM BLI in BSA-free medium (B10
=
91.5%) and 100
μM BLI in medium with BSA (B100
=
92.4%). Meiosis resumption occurred earlier in treated oocytes (71.4–74.3% in GV for B10 and B100, respectively, after 6
h IVM compared with 97.3% in controls,
P
<
0.05). By 18
h of IVM, most oocytes reached MII (72.0–78.9%,
P
>
0.05). Microtubules and microfilaments were unaffected by BLI. Cortical granules (CG) migration was reversibly blocked by BLI. Mitochondria translocation was partially blocked by PM culture and after IVM more oocytes in B10 and B100 (95.2 and 98.2%, respectively) had mitochondria translocated to a mature pattern (all cytoplasm) than controls (81.5%,
P
<
0.05). Cleavage rates were similar (81–87%,
P
>
0.05), but blastocysts (day 7) decreased in B100 (33.0%,
P
<
0.05) compared with controls and B10 (38.3 and 41.6%, respectively). Day 8 hatching rates (11.0–19.2%) and mean total cell numbers (136–150) were similar (
P
>
0.05). PM did not improve oocyte competence but also did not cause major structural alterations, suggesting that PM may be improved and used to study the mechanisms involved in oocyte differentiation.