Can the addition of Interleukin-13 affect the cryosurvival of bovine embryos?

In this study, we investigated the impact of incorporating Interleukin-13 (IL-13) into the embryonic culture medium and its influence on cryotolerance and cellular viability of vitrified bovine embryos. Two distinct time points for IL-13 supplementation were explored: during the final hours of culture prior to cryopreservation and during the period of recultivation following cryopreservation and warming. Cryosurvival rates, total cell count, and cell viability were assessed using the TUNEL technique to determine the apoptotic percentage. Re-expansion and hatching rates did not show differences among all groups (P > 0.05), and the total cell number was comparable between the treated and control groups (P > 0.05). However, the group that received IL-13 before vitrification exhibited a higher apoptotic percentage (P < 0.05). This suggests that the anti-inflammatory effect of IL-13 may have impacted the embryo's defense capacity against the stress induced by cryopreservation, leading to an increased percentage of apoptosis, although it did not influence the developmental resumption capability.

Effect of IL-10 and TNF-α on the competence and cryosurvival of in vitro produced Bos indicus embryos.

In vitro-produced embryos are constantly exposed to stressful conditions that can lead to the activation of the apoptotic pathway. The nuclear Kappa B factor (NF-κB) is an inflammatory mediator that induces the expression of tumor necrosis factor (TNF-α), a pro-inflammatory cytokine, while interleukin-10 (IL-10), an anti-inflammatory cytokine, inhibits NF-κB activity. This study aimed to investigate the effects of IL-10 and TNF-α on the competence and cryosurvival of in vitro-produced bovine embryos. Embryos were produced in vitro using standard protocols, and Grade I blastocysts were vitrified using the Cryotop method. Non-vitrified and vitrified blastocysts were subjected to the TUNEL assay. In Experiment I, on day 6.5 (156 h post-insemination), the embryos were treated with PBS (control), 50 ng/mL of IL-10, or a combination of 25 ng/mL of TNF-α and 50 ng/mL of IL-10. Embryonic development and apoptotic rates were monitored. In Experiment II, the same groups were set up, with the addition of a group treated with 25 ng/mL of TNF-α alone. Grade I blastocysts were vitrified 5 h after treatment, and cryosurvival was monitored at until 48 h post-warming. The apoptosis rate and total cell number were investigated in the vitrified-hatched blastocysts. IL-10 alone did not affect developmental competence or cryosurvival (P > 0.05). The IL-10-treated embryos, when exposed in combination with TNF-α, presented a detrimental effect (P < 0.05) in the embryonic development of non-vitrified embryos. However, vitrified blastocysts had no negative effect (P > 0.05). The TNF-α treatment reduced (P < 0.05) the re-expansion rate at 6 h post-warming and increased (P < 0.05) the apoptosis rate in vitrified hatched blastocysts, whereas no effect (P > 0.05) of the treatments was detected in the hatching rate and total cell number post-warming. In conclusion, TNF-α has a detrimental effect on embryonic developmental competence and cryosurvival by compromising the development of non-vitrified embryos and apoptotic-related events of vitrified blastocysts, whereas IL-10, when in combination with TNF-α, appears to attenuate the detrimental effects of TNF-α.