Embryotoxicity evaluation of Gentamicin, an aminoglycoside antibiotic added to human embryo culture medium, using the zebrafish (Danio rerio) model

Infertility gives rise to a lot of social and psychological problems. At present, assisted reproductive technology (ART) is an important way to solve infertility. However, the live birth rate of in vitro fertilization and embryo transfer (IVF-ET) is less than 50 %. Medium is essential for the culture of embryos in vitro. Therefore, we want to explore whether the composition of the culture medium affects the survival rate of embryos. Gentamicin (GM) is an aminoglycoside antibiotic that is used to treat various bacterial infections. It is widely used in IVF medium, but it is not known whether it has a toxicity effect on embryonic development. Here, we used zebrafish embryos to investigate the embryotoxicity of GM which is an ingredient in culture medium. Our results found that there was no significant effect on the zebrafish embryo development, including survival rate, malformation rate and developmental time course, while zebrafish embryos were treated with GM at the culture medium concentration (10 mg/L, 17.8 μM) compared with the control group. To research the potential embryotoxicity of GM, we treated zebrafish embryos with GM with high concentration (range from 17.8 μM to 3000 μM). The results showed that the lethal concentration of 50 % (LC50) at 48-h post-fertilization (hpf) value of zebrafish embryos for GM was 1150 μM; the survival rate and malformation rate of zebrafish embryos were significantly changed in a dose-dependent manner. Furthermore, transcriptomics, metabolomics and epigenomics (m6A-MeRIP-seq) were used to investigate the molecular mechanism of embryotoxicity, and results showed cell cycle, dorso-ventral axis formation and collecting duct acid secretion pathway were altered significantly in treated embryos. In conclusion, there are no adverse effects on embryonic development with the working concentration of GM in human culture medium, suggesting that GM is safe for embryo culture at working concentration.