In vitro maturation of ovine oocyte in a modified granulosa cells co-culture system and alpha-tocopherol supplementation: effects on nuclear maturation and cleavage.
This study was designed to investigate the effects of α-tocopherol and granulosa cells monolayer on nuclear maturation and cleavage rates of ovine cumulus-oocyte complexes (COCs). The COCs (n = 2814) were matured in maturation medium supplemented with various concentration of α-tocopherol (0, 5, 10, 15 μg/ml), oocytes were incubated at 39 °C with 5 % CO2 for 24 h in three culture systems: (a) maturation medium (MM; n = 884), (b) co-cultured with granulosa cells (CG; n = 982) and (c) co-cultured with granulosa cells and cells were further cultured in MM for 12 h (CG + 12hMM; n = 948). Our results showed that α-tocopherol had no effect on GVBD and MII as compared to control group, but when α-tocopherol added to maturation medium the rate of cleavage decreased. This indicates interaction of above mentioned factors in any of the treatments showed no significant differences on the rate of maturation and cleavage stages (MII, GVBD and cleavage) (p > 0.05). The oocytes co-cultured with granulosa cells for 24 h had beneficial effects on cleavage rate. The maximum MII and cleavage rates were achieved when oocytes had extra 12 h culture in the maturation medium without granulosa cells. Results also showed our modified co-culture system (CG + 12hMM), improved rates of MII and the cleavage in comparison with other studied maturation systems.
Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.
Hamideh
H
Adeldust
Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.
Saeed
S
Zeinoaldini
Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran ; Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University, Ahvaz, Iran.
Hamid
H
Kohram
Department of Animal Science, Shahid Bahonar University of Kerman, Kerman, Iran.
Mahmoud
M
Amiri Roudbar
National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
Morteza
M
Daliri Joupari
Embryo; Granulosa cell; In vitro fertilization; In vitro maturation