Myo-inositol in assisted reproductive technologies: Roles in sperm function, oocyte maturation, and embryo...

Assisted reproductive technologies (ARTs) are widely used in animal and human reproduction; however, their efficiency remains limited due to oxidative stress-induced damage to gametes and embryos during in vitro manipulation. Myo-inositol (Myo-Ins), a naturally occurring cyclitol and key precursor of phosphatidylinositol signaling molecules, has emerged as a promising modulator of reproductive performance due to its roles in intracellular signaling, redox regulation, and metabolic homeostasis. This review summarizes and critically evaluates current evidence regarding the role of Myo-Ins in ARTs, with a primary focus on porcine models and complementary insights from other mammalian species. In sperm, Myo-Ins has been shown to improve motility, mitochondrial function, and viability while reducing oxidative damage during liquid storage and cryopreservation, thereby preserving fertilizing capacity. During in vitro oocyte maturation (IVM), Myo-Ins appears to support cytoplasmic maturation by modulating intracellular calcium signaling, maintaining redox balance, enhancing mitochondrial activity, and improving lipid metabolic dynamics, although porcine-specific evidence remains limited. In the context of in vitro embryo culture (IVC), Myo-Ins supplementation has been associated with improved cleavage kinetics, blastocyst formation, mitochondrial integrity, and reduced apoptosis, potentially through indirect regulation of ROS and activation of antioxidant defense pathways such as NRF2 signaling. Current evidence from porcine and non-porcine models further suggests that the beneficial effects of Myo-Ins supplementation vary according to species, developmental stage, and IVC conditions, highlighting the importance of optimized and context-specific supplementation strategies in assisted reproduction. Importantly, the effects of Myo-Ins are dose- and stage-dependent, underscoring the need for optimized supplementation strategies. Collectively, available data indicate that Myo-Ins functions as a targeted redox and metabolic modulator rather than a conventional antioxidant, offering significant potential to improve ART outcomes across mammalian species, including porcine in vitro embryo production systems. Further mechanistic and translational studies are required to define optimal conditions and fully elucidate its mode of action across different stages of in vitro embryo production.