title: Use of retinoids during oocyte maturation diminishes apoptosis in caprine embryos.
abstract: Exposure of caprine oocytes and embryos to retinoids enhances embryonic development, but the mechanisms governing this phenomenon have not been characterised. The aim of the present study was to evaluate if the incidence of apoptosis is affected by the addition of retinyl acetate (RAc) and 9-cis-retinoic acid (RA) during in vitro maturation (IVM) of caprine oocytes. Embryonic development was recorded on days 3 and 8 post-fertilisation, and apoptosis was measured by caspase activity and DNA fragmentation (TUNEL assay). Control zygotes had lower capacity to cleave and reach the blastocyst stage (24.45 ± 2.32 and 5.32 ± 0.81, respectively) than those of RAc- (29.96 ± 1.62 and 7.94 ± 0.93, respectively) and RA-treated groups (30.12 ± 1.51 and 7.36 ± 1.02, respectively). Oocytes and blastocysts positive for TUNEL assay were more frequent, respectively, in the controls (8.20 ± 0.78, 8.70 ± 1.05) than in RAc (5.60 ± 0.52, 4.80 ± 0.51) and RA (6.40 ± 0.69, 5.40 ± 0.69). Caspase activity did not differ between control oocytes (7.20 ± 0.91), RAc (6.60 ± 0.68) and RA (7.30 ± 0.67), but it was reduced in RAc- (5.05 ± 0.62) and RA-treated blastocysts (5.75 ± 0.22) compared to controls (8.35 ± 0.71). These results indicate that the addition of retinoids during IVM increases the developmental potential of goat embryos with a concomitant reduction in apoptosis rates.
authors.affiliation: Department of Veterinary Medicine, Federal Rural University of Pernambuco , Av. Dom Manoel de Medeiros, s/n, Dois Irmãos, CEP 52171-900 Recife, Pernambuco , Brazil.
authors.forename: Juliana C Z
authors.initials: JC
authors.lastname: Conceição
authors.forename: Marcelo T
authors.initials: MT
authors.lastname: Moura
authors.forename: José C
authors.initials: JC
authors.lastname: Ferreira-Silva
authors.forename: Pamela
authors.initials: P
authors.lastname: Ramos-Deus
authors.forename: Priscila G C
authors.initials: PG
authors.lastname: Silva
authors.forename: Ludymila F
authors.initials: LF
authors.lastname: Cantanhêde
authors.forename: Ricardo M
authors.initials: RM
authors.lastname: Chaves
authors.forename: Paulo F
authors.initials: PF
authors.lastname: Lima
authors.forename: Marcos A L
authors.initials: MA
authors.lastname: Oliveira
keywords: In vitro maturation; embryogenesis; goat; programmed cell death; vitamin A