Long-term Copper Exposure Induces Mitochondrial Dynamics Disorder and Mitophagy in the Cerebrum of Pigs

Copper (Cu) is an essential trace element for growth and development in most organisms. However, environmental exposure to high doses of Cu can damage multiple organs. To investigate the underlying mechanism of Cu toxicity on mitochondrial dynamics and mitophagy in the cerebrum of pigs, 60 30-day-old pigs were randomly divided into three groups and treated with different contents of anhydrous Cu sulfate in the diets (Cu 10 mg/kg, control group; Cu 125 mg/kg, group I; Cu 250 mg/kg, group II) for 80 days. The Cu levels and histological changes in the cerebrum were measured. Moreover, the protein and mRNA expression levels related to mitophagy and mitochondrial dynamics were determined. The results showed that the contents of Cu were increased in the cerebrum with increasing dietary Cu. Vacuolar degeneration was found in group I and group II compared to the control group. Additionally, the protein and mRNA expression levels of PINK1, Parkin, and Drp1 and the protein level of LC3-II were remarkably upregulated with increasing levels of dietary Cu. Nevertheless, the protein and mRNA expression levels of MFN1 and MFN2 and the mRNA expression of P62 were obviously downregulated in a Cu dose-dependent manner. Overall, these results suggested that excess Cu could trigger mitochondrial dynamics disorder and mitophagy in the pig cerebrum, which provided a novel insight into Cu-induced toxicology.