Optimizing maturation of oocytes with nitric oxide-loaded microbubbles.

Introduction: Nitric oxide (NO) plays a pivotal role in female reproductive processes, yet its clinical translation is limited by its short half-life and rapid systemic clearance. This study aimed to develop a stabilized NO delivery system to enhance oocyte maturation and quality for potential applications in assisted reproductive technologies (ART).

Methods: Lipid-based microbubbles (NO-MBs) were constructed via lyophilization to encapsulate and stabilize therapeutic NO gas. The effects of NO-MBs on in vitro oocyte maturation were evaluated using immature mouse oocytes, with conventional NO donors (e.g., SNP) as controls. Oocyte quality was assessed through Ca2+ levels, mitochondrial membrane potential (MMP), and intracellular reactive oxygen species (ROS). studies further examined oocyte retrieval, fertilization rates, and blastocyst cell apoptosis. Mechanistic investigations focused on the ERK signaling pathway.

Results: The key parameters of the optimized lipid-based microbubbles for NO gas delivery were as follows: particle concentration (2.23 × 10 MBs/mL) and diameter (0.919 ± 0.807 μm). NO-MBs demonstrated superior biosafety and efficacy compared to conventional NO donors. , NO-MBs significantly increased the maturation rate of immature mouse oocytes (72.00% vs. 57.77% in controls) while improving oocyte quality, as evidenced by elevated Ca2+ levels, enhanced MMP, and reduced ROS. , NO-MBs enhanced oocyte retrieval and fertilization rates and reduced blastocyst cell apoptosis. Mechanistically, NO-MBs uniquely activated phosphorylated ERK, suggesting ERK pathway involvement in oocyte maturation.

Discussion: These findings highlight NO-MBs as a novel, clinically relevant strategy for targeted NO delivery in reproductive medicine. By optimizing NO release and bioavailability, NO-MBs offer a promising approach to improve oocyte quality and developmental outcomes in ART. Further studies are warranted to explore their broader applications in reproductive health.