Impacts of metal elements on oxidative stress and A protein deposition in SH-SY5Y cells

Objective To study the effects of copper (Cu),iron (Fe),zinc (Zn),and aluminum (Al) exposure on oxidative stress and beta amyloid (Aβ) protein deposition in human neuroblastoma cell line (SH-SY5Y) and to provide evidences for senile dementia prevention.Methods SH-SY5Y cells were treated with various doses of Cu,Fe,Zn,and Al,respectively.The viability of the cells was determined with 3-4,5-dimedthylthiazol-2,5-diphenyltetrazolium bromide (MTT) assay.The activity of superoxide dismutase (SOD) in cultured SH-SY5Y cells was detected with xanthine oxidase method;the activity of glutathione peroxidase (GSH-PX) was measured with colorimetry;the content of malondialdehyde (MDA) in culture supematant fluid was assessed with thiobituric acid reaction (TBA) method.Cellular reactive oxygen species (ROS) level was detected using fluorescent probe of 2',7'-dichlorofluorescein diacetate (DCFH-DA).The content of Aβ_1-42 was measured by enzyme-linked immunosorbent assay (ELISA).Results Cu,Fe,Zn,and Al could suppress the viability of SH-SY5Y cells in a concentration-dependent manner.When treated with copper sulfate (CuSO₄) at the dosages of 50,200,and 400 μmol/L,the survival rates of the SH-SY5Y cells were 90.47%,74.81%,and 64.97%;at the dosages of 1,2,and 4 mmol/L,the survival rates of the SH-SY5Y cells were 93.08%,78.28%,and 56.10% when exposed to ferrous sulfate (FeSO₄) and 2.21%,85.30%,and 62.72% when exposed to aluminum chloride (AlCl₃);the survival rates of the the SH-SY5Y cells were 91.76%,76.51%,and 61.27% when treated with zinc sulfate (ZnSO₄) at the dosages of 50,100,and 200 μmol/L,respectively.The survival rates of the SH-SY5Y cells exposed to various concentrations of the four metallic compounds were all significantly lower than that of the blank control group (P<0.05 for all).When treated with the four metallic compounds,the intracellular activity of SOD decreased but the intracellular ROS increased significantly;the activity of GSH-PX declined but the content of MDA and Aβ_1-42 increased significantly in culture supematant fluid compared to those of the control (all P<0.05).Conclusion Copper,iron,zinc,and aluminum compounds could induce damage in SH-SY5Y cells and result in deposition of Aβ protein by ROS generation and oxidative stress pathway.