In this study, we investigated the induction of oxidative stress and apoptosis in human neuroblastoma cell line SH-SY5Y in response to alpha-cypermethrin (α-CYPER) exposure. MTT and LDH assays were carried out to assess the α-CYPER cytotoxicity. The IC50 value for α-CYPER was calculated to be 78.3 ± 2.98 µM for the MTT assay and 71.5 ± 3.94 µM for LDH assay. The pyrethroid α-CYPER (1-100 µM), in a dose-dependent manner, induced a significant increase in lipid peroxides measured as malondialdehyde (MDA) and in the levels of nitric oxide (NO). The neuroprotective role of three antioxidants, melatonin (MEL), Trolox and N-acetylcysteine (NAC) against α-CYPER-induced oxidative stress was examined. Compared to other antioxidants, MEL (1 µM) treatment showed the most effective protection against α-CYPER-induced lipid peroxidation and NO production. The effects of α-CYPER on gene expression profiling of cell death pathway in human neuroblastoma SH-SY5Y cells were also investigated. Of the 84 genes examined (P < 0.001; fold change >1.5), changes in mRNA levels were detected in 39 genes: 36 were up-regulated and 3 were down-regulated. A greater fold change reversion than 3.5-fold was observed on the up-regulated ATP6V1G2, BCL2, CASP9, FAS, GADD45A, SPATA2, SYCP2, ATG7, NFKB1, SNCA, ULK1 and JPH3 genes. The results demonstrated that α-CYPER alters the expression of apoptosis-, autophagy- and necrosis genes as well as induces oxidative stress which may lead to DNA damage. The detailed knowledge of the changes in gene expression obtained will provide a basis for further elucidating the molecular mechanisms of the α-CYPER-induced toxicity.
Keywords: Cell death pathways; Melatonin neuroprotection; Microarray; Neurotoxicity; SH-SY5Y cells; α-Cypermethrin.