In vitro developmental competence of prepubertal goat oocytes cultured with recombinant activin-A

Abstract

The present study was designed to evaluate the effect of activin-A during the in vitro oocyte maturation (IVM) and in vitro embryo culture (IVC) on nuclear maturation, blastocyst yield and blastocyst quality of prepubertal goat oocytes. In Experiment 1, three groups of oocytes were used during the IVM of prepubertal goat oocytes to determine the optimal concentration of recombinant human activin-A added to the maturation medium. Cumulus-oocyte complexes were matured in an IVM medium containing 0, 10 and 100 ng/ml (groups A0, A10 and A100), fertilized and in vitro cultured using standard procedures. In Experiment 2, the addition of 10 ng/ml activin-A at IVM (A10A0), IVC (A0A10) or IVM + IVC (A10A10) was studied and compared with the control group (A0A0). Results of the first experiment demonstrated that the addition of activin-A yielded similar percentages of maturation (⩽71.0%) and blastocyst formation rates (⩽24.9%) than the control group (A0). Experiment 2 showed that exposure of prepubertal goat oocytes to an IVC medium containing 10 ng/ml activin-A (A0A10) significantly increased the rates of development to the blastocyst stage, as compared with the control group (A0A0) (19.5 ± 2.21% v. 13.1 ± 2.37%, respectively; P < 0.05). With regard to the blastocyst quality, total number of cells, inner cell mass (ICM) and trophectoderm of prepubertal goat embryos produced in the presence of activin-A did not differ significantly among experimental groups. In summary, these results indicate that supplementation of the IVC medium with activin-A enhances embryo development of prepubertal goat oocytes.

Activin‐A receptor expression patterns in prepubertal goat oocytes and derived embryos

“…Considering that activin-A type II receptors were detectable in matured oocytes by Western blotting but were not detected by immunocytochemistry, we speculate that type II activin-A receptors are synthesized during oocyte maturation and expressed at the membrane level after fertilization. This fact could explain why in our previous study (Hammami et al, 2014), we did not find any effect of the addition of the activin-A to the IVM medium on nuclear stage and blastocyst development. However, activin-A added to the embryo culture medium increased blastocyst development.…”

“…The in vitro embryo production procedure followed has been described previously (Hammami et al, ). Ovaries from 1‐ to 2‐month‐old goats were recollected from a slaughterhouse.…”

“…The in vitro embryo production procedure followed has been described previously (Hammami et al, 2014). Ovaries from…”

“…In a previous report, we showed that the addition of activin to the in vitro maturation (IVM) medium of prepubertal goat oocytes did not improve nuclear maturation nor blastocyst development. However, the addition of 10 ng/ml of activin-A at the in vitro embryo culture medium increased significantly blastocyst output (Hammami, Izquierdo, Catalá, Paramio, & Morató, 2014). The binding of activin to a type II receptor causes the activation of a type I receptor by a mechanism of phosphorylation triggering a cascade of events that results in the regulation of a target gene transcription (Ethier & Findlay, 2001).…”

Use of retinoids during oocyte maturation diminishes apoptosis in caprine embryos

“…In goats, several reports have demonstrated that factors such α-lipoic acid, activin-A and retinoids enhance embryonic development when supplemented during oocyte maturation and/or embryo culture (Bormann et al, 2003;Chiamenti et al, 2010;Kwong et al, 2012;Zhang et al, 2013;Hammami et al, 2014). Vitamin A and its physiological metabolites, collectively known as retinoids, play important roles in embryonic morphogenesis and reproductive physiology as a mitogenic and differentiation stimulus (Hofmann and Eichele, 1994).…”