STEAP3-SLC39A8-mediated microglia ferroptosis involved in neurotoxicity in rats after exposure to lead and cadmium combined

The exposure of humans and animals to environmental compounds is rarely restricted to a single chemical. Unfortunately, very few studies were conducted to determine cadmium and lead combined effect. The aim of this study was to clarify the neurotoxicity induced by combined exposure to lead and cadmium and its mechanism of action. Sprague Dawley (SD) rats were randomly divided into control, lead, cadmium, and combined lead and cadmium groups, and Y-maze was used to detect the learning and memory ability of the rats, and the hippocampal tissue was subjected to HE pathology staining. Detection of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and reduced glutathione (GSH) and inflammatory factors IL-1β, TNF-α levels, immunofluorescence for microglia marker Iba1, and western blot for ferroptosis-related proteins SLC7A11, GPX4, and FTH1. Primary rat microglia were extracted, the combined dose was determined by CCK8, and the differentially expressed proteins were identified by 4D-DIA quantitative proteomics technology. The differentially expressed proteins were analyzed by KEGG analysis software for bioinformatics, and the results were verified by immunofluorescence. The results showed that combined exposure to lead and cadmium decreased the learning and memory ability of the rats, and the levels of lead and cadmium in the blood and the hippocampus increased, and the expression of microglia marker Iba1 in the hippocampus was elevated, and the expression of inflammatory factors IL-1β and TNF-α was elevated, combined exposure decreased GSH and SOD levels, increased ROS and MDA levels, increased iron content, and decreased expression of iron death-related proteins SLC7A11, GPX4 and FTH1. Extracted rat primary microglia, CCK8 to determine the co-toxicity dose after proteomics testing, found that iron metabolism-related protein SLC39A8 was down-regulated, STEAP3 was up-regulated, and validation results were consistent with the proteomics results. Conclusion, combined lead and cadmium exposure may exacerbate neurotoxicity by mediating microglia ferroptosis via STEAP3, SLC39A8.