Efeitos da suplementação de nanopartículas de óxido de zinco sobre o desenvolvimento de embriões bovinos produzidos in vitro

Abstract

In vitro production of bovine embryos faces significant limitations associated with oxidative stress generated by suboptimal culture conditions, which compromise oocyte competence and embryo viability. Zinc acts as an essential metabolic regulator and enzymatic cofactor in this process, and zinc oxide nanoparticles are an innovative strategy to increase its bioavailability and cellular interaction. The objective of the present study was to investigate the effects of supplementing different concentrations of NPZnO during in vitro maturation on oocyte quality and bovine embryo development. The results showed that the concentration of 1.5 µg/mL promoted the highest blastocyst production rate (60.5%), statistically superior to the control group (51.8%; p<0.05), while the concentration of 7.5 µg/mL induced toxicity, blocking oocyte nuclear maturation, increasing ROS and the apoptotic index of blastocysts. p<0.05), while the concentration of 7.5 µg/mL induced toxicity, blocking oocyte nuclear maturation, increasing ROS and the apoptotic index of blastocysts (p<0.05). Despite the beneficial effect of the 1.5 µg/mL concentration, there was no significant difference in the level of ROS in oocytes compared to the control group (p>0.05), and an increase in lipoperoxidation was observed in embryos (55.1% compared to 49.9% in the control group; p<0.05), suggesting adaptive metabolic activation. It is concluded that NPZnO have a dose-dependent effect and indicate possible hormetic behavior, with better performance observed at a concentration of 1.5 µg/mL in bovine IVEP. This study shows that modulation by nanoparticles supports embryonic development within a therapeutic window, acting through signaling and metabolic regulation pathways, independently of a classic antioxidant effect of direct neutralization of free radicals.