Bovine amniotic membrane stem cell-conditioned medium improves the culture conditions for in vitro produced ovine embryos

Despite the progress in in vitro embryo production technology, the quality of embryos produced in vitro remains inferior to that of embryos produced in vivo. There have been reports highlighting the beneficial impacts of stem cells and their conditioned medium on the in vitro maturation of oocytes and the in vitro culture of embryos. In this study, we investigated the effects of adding bovine amniotic membrane stem cell-conditioned medium (bAMSC-CM) to the IVC medium of ovine embryos. Moreover, the effects of bAMSC-CM were compared with the effects of charcoal-stripped fetal bovine serum (CSS). In the first experiment, culture media refreshment was performed on the third day of IVC (day 0 = IVF). The addition of bAMSC-CM and CSS to the IVC medium was conducted in three different ways: from day 1-3 of IVC, from day 1-7 of IVC, and from day 3-7 of IVC. In the second experiment, no culture medium renewal was conducted, and CSS and bAMSC-CM were added from the first day of IVC until the seventh day (CSS and CM groups). In both experiments, a control group (Con) was included that did not receive any supplementation. The data of embryonic cleavage of various treatments was aggregated. The cleavage rate of the embryos cultured in the CM-containing medium from the first day of IVC (CM1) was higher compared with the cleavage rate of the embryos cultured in the Con medium (P < 0.05). In the first experiment, the addition of bAMSC-CM from the onset of IVC resulted in a significant improvement in the blastocyst rate, hatching rate, and blastocyst cell numbers compared with the Con group (P < 0.05). The inclusion of CSS from the first day of IVC resulted in a significant reduction in both blastocyst rate and quality (P < 0.05). The addition of CSS on the third day of IVC resulted in a significant increase in the blastocyst rate compared with the Con group (P < 0.05). In the second experiment, the blastocyst rate and blastocyst cell count in the CM group showed a significant increase compared with the CSS and Con groups (P < 0.05). In conclusion, supplementing ovine IVC medium with bAMSC-CM from the start of IVC increased blastocyst rate and improved the quality of the resulting blastocysts. Furthermore, the need to refresh the culture medium on the third day of the culture has been eliminated.