In vitro maturation of porcine oocytes with retinoids improves embryonic development

Abstract

Abstract. In the present study, the effects of retinoid metabolite administration during in vitro maturation (IVM) on oocyte maturation, parameters of in vitro fertilisation (IVF) and embryo development were examined. Varying concentrations of 9-cis retinoic acid (RA; 0, 5, 50 and 500 nm; Experiment 1) and all-trans retinol (ROH; 0, 125, 1250 and 12 500 nm; Experiment 2) were included in the maturation medium. Cumulus-oocyte complexes were matured in vitro and inseminated with frozen-thawed spermatozoa. Presumptive zygotes were cultured for 16 h to assess IVF parameters or for 7 days to assess embryo development and quality. In Experiment 1, the oocyte maturation rate to metaphase II was significantly decreased (P < 0.001), with values below 5%, in the presence of the highest concentration of RA (500 nm). However, 5 and 50 nm RA had no effect compared with control. Treatment with 5 nm RA improved the blastocyst development rate (P < 0.001). In Experiment 2, the oocyte maturation rate did not differ between 125 and 1250 nm ROH treatment groups and control. However, treatment with 12 500 nm ROH was deleterious because no matured oocytes were observed following the treatment. The penetration rate was lower in the group treated with 1250 nm ROH compared with the 125 nm ROH-treated and control groups, but the blastocyst formation rate did not differ among the three groups. In conclusion, 5 nm RA in the IVM medium significantly increased the blastocyst formation rate, suggesting that RA may play an important role during IVM.

Effect of all-trans retinol on in vitro development of preimplantation buffalo embryos

“…The present results are in disagreement with those obtained in porcine IVF, where it has been reported that treatment of oocytes with all-trans retinol resulted in better embryo cleavage compared with control, this enhancement was not reflected in blastocyst development, whereas the presence of 5 nm 9-cis retinoic acid in the IVM medium significantly increased the blastocyst formation rate, suggesting that 9-cis-retinoic acid may play an important role during IVM (Alminana et al, 2008). A possible explanation for these discrepancies could be the different IVM conditions used by these authors, where the oocytes are matured for 20-22 h with supplements and another 20-22 h without supplements.…”

Effects of retinoic acid on maturation of immature mouse oocytes in the presence and absence of a granulosa cell co-culture system

“…The beneficial effects of retinol metabolites on in vitro cytoplasmic maturation and embryo development have been previously described [5,6,12,20,25] however there are no reports about the simultaneous effects of t-RA and co-culture systems of granulosa cells on the developmental potency of cumulus-free immature oocytes. Following our previous observation [22], in the present study we have shown that the use of 2 μM t-RA in maturation medium with granulosa cell monolayer improves developmental competence of naked immature mice oocytes.…”

“…In a previous study, we have shown that the use of a physiological dose of all-trans retinoic acid (t-RA; 2 μM) during in vitro maturation and under precise conditions could improve both maturation and developmental competence of denuded immature mouse oocytes [22]. Therefore, based on this and other studies [5,6,12,[19][20][21][22] we assume that the cumulus granulosa cells might be a target for added RA during in vitro maturation, which could improve embryo development. In this study, we evaluate the effects of t-RA in association with a co-culture granulosa cell monolayer on the IVM of naked immature mice oocytes and then follow them until the blastocyst stage.…”

“…In 1999, it was shown that retinol improved in vitro embryo viability in sheep [12]. Some years later, it has been proven that the addition of RA during the IVM procedure improves early development of bovine oocytes [7].…”

“…In this manner, Mohan et al have shown that cumulus granulosa cells contain endogenously activated retinoid receptors that can reply to RA [19]. The beneficial effects of RA on in vitro maturation of cumulus oocyte complexes has been previously described [5,6,12,20,21] however no reports have discussed the effects of RA on the developmental competence of naked immature oocytes. In a previous study, we have shown that the use of a physiological dose of all-trans retinoic acid (t-RA; 2 μM) during in vitro maturation and under precise conditions could improve both maturation and developmental competence of denuded immature mouse oocytes [22].…”