The effect of curcumin against 6-hydroxydopamine induced cell death and Akt/GSK disruption in human neuroblastoma cells

Parkinson’s disease (PD) is the second most common neurodegenerative disease, characterized by the continuous deficit of dopaminergic neural cells in the substantia nigra pars compacta. The natural compounds from plant extracts, such as turmeric, have been proposed as alternative sources for anti-PD drugs. Human neuroblastoma SH-SY5Y is a dopaminergic neuronal cell line used as an in vitro model for the study of dopaminergic cells. The neurotoxin 6-hydroxydopamine (6-OHDA) has been known to induce cell death in dopaminergic neural cells. Curcumin, as the main ingredient of turmeric, has been shown to protect against some animal models of PD. The purpose of the present study was to assess the potential neuroprotective effect of curcumin against the 6-OHDA-induced cell death in SH-SY5Y cells and to delineate its effect on Akt/GSK-3β signaling. The cells were exposed to 6-OHDA with/without different doses of curcumin and their viability was examined via MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) and morphological observations. According to the MTT results, the protective doses of curcumin (2 and 2.5μM) were selected for further studies. Western blot assay was done to determine the phosphorylated and total amount of Akt and GSK-3β proteins. 6-OHDA induced cell death and declined Akt/GSK-3β phosphorylation, while curcumin co-treatment partially restored these effects. Taken together, these findings suggest that curcumin protects the SH-SY5Y cells from 6-OHDA-induced cell death and Akt/GSK-3β signaling alteration. Thus, our study indicates that curcumin has a partial cytoprotective effect in dopaminergic cell culture systems.