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2591556 
Journal Article 
Prematuration of bovine oocytes with butyrolactone I: Effects on meiosis progression, cytoskeleton, organelle distribution and embryo development 
Adona, PR; Lisboa Pires, PR; Quetglas, MD; Schwarz, KRL; Verde Leal, CL 
2008 
Yes 
Animal Reproduction Science
ISSN: 0378-4320 
108 
1-2 
49-65 
English 
17692479 
WOS:000259827400006 
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 mu M). Without BSA in PM medium, GV rates were similar (98.7-97.2, P > 0.05) with low BLI (10-25 mu M). 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 mu M BLI in BSA-free medium (B10=91.5%) and 10 mu M 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. (c) 2007 Elsevier B.V. All rights reserved. 
cattle; meiotic arrest; maturation; cytoskeleton; mitochondria; cortical granules