S-adenosyl-L-methionine reverses ethanol-induced developmental toxicity in FASD model of Danio rerio embryos via dual-modulation of oxidative stress and glutathione homeostasis

Abstract

Fetal Alcohol Spectrum Disorder (FASD) represents a major global public health concern, affecting approximately 7.7 per 1000 births worldwide and remains as the most common preventable cause of lifelong neurodevelopmental impairment. Despite its prevalence, current clinical interventions are largely symptom-supportive and fail to address the underlying developmental pathology, underscoring the need for targeted, mechanism-based therapeutic strategies. Given the central involvement of oxidative stress and inflammation in FASD pathogenesis, this study evaluated the protective efficacy of S-adenosyl-L-methionine (SAMe), a key metabolic intermediate and universal methyl donor, using a zebrafish embryo model because of its high translational relevance and optical transparency. Fertilized embryos were exposed to 1.25% ethanol and co-treated with SAMe (15 and 30 μM) until 96 h post-fertilization (hpf). Ethanol exposure resulted in reduced survival and hatching rates, cardiac rhythm abnormalities, pronounced morphological defects, and compromised tissue integrity. SAMe treatment, particularly at 30 μM, significantly ameliorated these developmental abnormalities and associated biochemical dysregulations. Mechanistically, SAMe exerted a dual protective effect by restoring glutathione biosynthesis and attenuating oxidative stress-driven inflammatory responses. This was evidenced by marked reductions in reactive oxygen species, apoptosis, lipid peroxidation, and nitric oxide levels, alongside significant downregulation of pro-inflammatory cytokines, including TNF-α and IL-1β. Importantly, these biochemical and molecular improvements were consistently translated into phenotypic rescue, with substantial normalization of tissue architecture and developmental morphology. Collectively, these findings establish SAMe as a promising anti-teratogenic intervention that directly targets core oxidative and inflammatory pathways underlying FASD, highlighting its potential translational relevance as a mechanism-driven therapeutic strategy.