(37) Sulforaphane Fails to Alleviate Oxidative Stress and Impairs Oocyte Maturation in Porcine Embryo Culture

Allison Ojerio¹, Werner Glanzner¹, Karina Gutierrez¹, Fernanda Facioli¹, Mariana Priotto de Macedo¹, Zigomar da Silva¹, Luke Currin¹, Vanessa Guay¹, Vilceu Bordignon¹

1.     Department of Animal Science, McGill University, Montreal, Canada


Abstract Text:

Oxidative stress (OS) is known to impair early embryonic development and reduce the overall quality of in vitro-produced embryos. Sulforaphane (SFN), a naturally occurring compound found in leafy greens, has been shown to disrupt the KEAP1-NRF2 interaction, preventing KEAP1 from targeting NRF2 for degradation and thereby increasing NRF2 levels. NRF2 translocates into the nucleus and binds to antioxidant response elements (AREs), leading to enhanced antioxidant defenses.

The goal of this study was to investigate whether SFN supplementation could mitigate the effects of OS during porcine in vitro embryo production. First, SFN was tested during either in vitro maturation (IVM) of oocytes or in vitro embryo culture (IVC) at concentrations of 1 µM, 5 µM, and 10 µM. Supplementation during IVM with 5 µM and 10 µM SFN significantly decreased oocyte maturation rates, as indicated by a lower proportion of oocytes reaching the Metaphase II stage, whereas maturation was not affected by the 1 µM concentration. Following parthenogenetic activation of matured oocytes, embryo cleavage and blastocyst rates were significantly lower in oocytes matured with 10 µM SFN compared to controls. While SFN supplementation during IVC did not significantly affect blastocyst formation rates, embryos cultured with higher concentrations (5 µM and 10 µM) exhibited a significant reduction in total cell number per blastocyst. Next, SFN was added to the embryo culture medium at 1 µM or 5 µM, either from Day 1 to Day 7 (D1-D7) or from Day 3.5 to Day 7 (D3.5-D7). While blastocyst rates were not significantly different among treatments, embryos treated from D1-D7 had a lower total cell number per blastocyst compared to those treated from D3.5-D7. Finally, the ability of SFN to protect embryos from OS was assessed by supplementing the culture medium with 1 mM glucose and either 1 µM or 5 µM SFN from D1-D7. While glucose supplementation reduced both blastocyst rates and total cell number per blastocyst compared to non-treated embryos, SFN supplementation at either concentration failed to rescue embryos from these detrimental effects.

Our findings suggest that SFN supplementation is not a viable strategy for mitigating OS during porcine embryo culture and may have adverse effects on oocyte maturation and embryo development. Further studies are needed to elucidate the underlying mechanisms of SFN's negative impact on embryo development.