Honokiol reduces cadmium-induced oxidative injury and endosomal/lysosomal vacuolation via protecting mitochondrial function in quail (Coturnix japonica) liver tissues

Cadmium (Cd) pollution in environment is toxic to birds. This study aimed to assess antagonistic effect of honokiol (HNK) on Cd-induced quail (Coturnix japonica) liver tissue damage and Cd-induced vacuolation in hepatocytes. We found that HNK alleviated Cd-induced liver pathological damage marked by elevated serum liver biochemical indicators, disordered antioxidant levels and trace elements in quails. HNK reduced Cd-induced liver cell apoptosis as assessed by western blotting and TUNEL staining. The ultrastructure of hepatocytes under transmission electron microscope revealed that Cd induced mitochondrial damage in addition to abnormal enlargement and increased vacuolar structure of cells. Mitochondrial damage and vacuolization were reduced in the HNK + Cd group. Cd induced an increase in the levels of endosomal/lysosomal-related genes, while HNK treatment reversed this effect. Finally, we demonstrated that vacuolation in buffalo rat liver 3A (BRL 3A) cells occurred primarily due to Cd-induced oxidative stress damage that reduces mitochondrial ATP content and indirectly led to dysfunction of ATP-dependent lipid kinase PIKfyve complex. In summary, we are the first to report that Cd induces abnormal enlargement of endosome/lysosomes in quail liver cells and HNK alleviated this phenomenon by reducing mitochondrial damage and increasing intracellular ATP level. This study demonstrated the toxic effect of Cd pollution on birds and how HNK mitigated these effect at the cellular level. Overall, more research on Cd pollution and HNK use in animal husbandry is warranted.