Exposure to copper induces oxidative stress and apoptosis in human MEG-01 cells.

BACKGROUND Wilson disease (WD), caused by ATP7B mutations, leads to pathological copper accumulation. Although thrombocytopenia is often reported in patients with WD, the underlying mechanisms are complex and remain unelucidated. This study used the human megakaryoblast cell line MEG-01 to investigate how excess copper affects cellular oxidative stress and apoptosis.

METHODS After exposing MEG-01 cells to CuCl₂ for 24 h, viability was determined using a Cell Counting Kit-8 (CCK-8) assay, and intracellular ultrastructural changes were observed using transmission electron microscopy (TEM). Apoptosis was quantified using annexin V/propidium iodide (PI) staining combined with flow cytometry analysis. Reactive oxygen species (ROS) levels were analyzed by 2',7'-dichlorodihydrofluorescein diacetate staining and flow cytometry. Malondialdehyde (MDA) and superoxide dismutase (SOD) were detected using thiobarbituric acid (TBA) and water-soluble tetrazolium 8 (WST-8) assays, respectively. The expression levels of p62 and caspase-3 proteins were evaluated using western blotting.

RESULTS Compared with the control group, CuCl2 treatment of MEG-01 cells significantly inhibited the viability of cells. TEM revealed mitochondrial swelling, cristae fragmentation, and endoplasmic reticulum dilatation, indicating organelle damage. The apoptotic rate exhibited a dose-dependent increase in response to CuCl2, which was paralleled by a significant upregulation in the protein levels of caspase-3 and p62. Finally, treatment of MEG-01 cells with CuCl₂ significantly elevated the levels of ROS and MDA. While SOD activity remained unchanged in the 10 and 20 μM CuCl2 groups compared to the control, it was markedly reduced following exposure to 40 μM CuCl2.

CONCLUSION Copper exposure damages MEG-01 cells. This is likely mainly due to oxidative stress and apoptosis.