Protective effects and mechanism of chemical- and plant-based selenocystine against cadmium-induced liver damage

Although selenium (Se) and cadmium (Cd) often coexist naturally in the soil of China, the health risks to local residents consuming Se-Cd co-enriched foods are unknown. In the present study, we investigated the effects of chemical-based selenocystine (SeCys₂) on cadmium chloride-induced human hepatocarcinoma (HepG2) cell injury and plant (Cardamine hupingshanensis)-derived SeCys₂ against Cd-induced liver injury in mice. We found that chemical- and plant-based SeCys₂ showed protective effects against Cd-induced HepG2 cell injury and liver damage in mice, respectively. Compared with Cd intervention group, co-treatment with chemical- or plant-based SeCys₂ both alleviated liver toxicity and ferroptosis by decreasing ferrous iron, acyl-CoA synthetase long-chain (ACSL) family member 4, lysophosphatidylcholine acyltransferase 3, reactive oxygen species and lipid peroxide levels, and increasing ACSL3, peroxisome proliferator-activated receptor α, solute carrier family 7 member 11 (SLC7A11) and glutathione and glutathione peroxidase 4 (GPX4) levels. In conclusion, chemical- and plant-based SeCys₂ alleviated Cd-induced hepatotoxicity and ferroptosis by regulating SLC7A11/GPX4 signaling and lipid peroxidation. Our findings indicate that potential Cd toxicity from consuming foods grown in Se- and Cd-rich soils should be re-evaluated. This study offers a new perspective for the development of SeCys₂-enriched agricultural products.