Lead Exposure Triggers Ferroptotic Hepatocellular Death in Zebrafish: Molecular and Ultrastructural Evidence

Lead (Pb) has progressively become ubiquitous due to widespread use. The liver represents a target of Pb toxicity due to its central role in metabolism and detoxification. The mechanisms of Pb hepatotoxicity have not yet been fully elucidated, although oxidative stress and iron dysregulation suggest the involvement of the ferroptosis pathway. It has been hypothesized that exposure to environmental Pb concentrations induces the activation of ferroptosis as a mechanism involved in Pb hepatotoxicity, an iron-mediated regulated cell death. To test this hypothesis, we exposed adult zebrafish to environmentally relevant Pb concentrations (2.5 and 5 μg/L), combining ultrastructural analysis (TEM) with the study of key markers of ferroptosis (GPX4, SLC7A11, NRF2, KEAP1 and ACSL4). The results demonstrated that Pb exposure induced dose-dependent and progressive mitochondrial damage in hepatocytes, characterized by loss of cristae and membrane rupture. At the same time, consistent with a ferroptotic molecular profile, increased expression of ACSL4, reduced levels of the protective factors NRF2, KEAP1 and SLC7A11, and altered expression of GPX4 were observed. Overall, our data collectively identify ferroptosis as a pathogenic pathway in Pb-induced hepatotoxicity.