Prematuration of bovine oocytes with butyrolactone I: effects on meiosis progression, cytoskeleton, organelle distribution and embryo development.
The effects of prematuration (PM) of bovine oocytes with butyrolactone I (BLI) for 24h 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 (100-25microM). Without BSA in PM medium, GV rates were similar (98.7-97.2, P>0.05) with low BLI (10-25microM). After in vitro maturation (IVM) for 24h, metaphase II (MII) rates for controls (IVM only) were similar (91.1%, P>0.05) to PM with 10microM BLI in BSA-free medium (B10=91.5%) and 100microM 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 6h IVM compared with 97.3% in controls, P<0.05). By 18h 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.
Adona
Paulo Roberto
PR
Departamento de Ciências Básicas, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Brazil.
Pires
Pedro Ratto Lisboa
PR
Quetglas
Maria Daniela
MD
Schwarz
K R L
KR
Leal
Cláudia Lima Verde
CL
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002417:Cattle / Q000196:embryology*; D003599:Cytoskeleton / Q000187:drug effects* / Q000502:physiology; D004622:Embryo, Mammalian / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects* / Q000502:physiology; D005307:Fertilization in Vitro / Q000662:veterinary; D008540:Meiosis; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D015388:Organelles / Q000502:physiology*
C082868:butyrolactone I; D015107:4-Butyrolactone