Involvement of oxidative stress in di-2-ethylhexyl phthalate (DEHP)-induced apoptosis of mouse NE-4C neural stem cells

Abstract

Di-2-ethylhexyl phthalate (DEHP) has been widely used as a plasticizer in industry and can cause neurotoxicity; however, the underlying mechanism remains unclear. In the study, we found that DEHP significantly inhibited viability of mouse NE-4C neural stem cells and caused lactate dehydrogenase (LDH) release from the cells. DEHP dramatically increased the levels of apoptosis-related proteins such as cleaved Caspase-8, cleaved Caspase-3 and Bax, as well as decreased Bcl-2 protein level. DEHP could also significantly increase the total numbers of AnnexinV-positive/PI-negative and AnnexinV-positive/PI-positive staining cells. Hoechst 33342 staining showed that marked DNA condensation and apoptotic bodies could be found in the ZnO NPs-treated cells. These results indicated that DEHP could induce apoptosis of NE-4C cells. Meanwhile, DEHP could significantly increase malondialdehyde (MDA) level, and decrease the content of glutathione (GSH) and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), respectively, implying that DEHP could induce oxidative stress of NE-4C cells. Furthermore, N-Acetyl-l-cysteine (NAC), an inhibitor of oxidative stress, could rescue the inhibition of cell viability and induction of apoptosis by DEHP. Taken together, our results showed that oxidative stress was involved in DEHP-induced apoptosis of mouse NE-4C cells.