Protective effect of arachidonic acid and linoleic acid on 1-methyl-4-phenylpyridinium-induced toxicity in PC12 cells

Background: Parkinson's disease is a neurodegenerative disorder that is being characterized by the progressive loss of dopaminergic neurons of the nigrostriatal pathway in the brain. The protective effect of omega-6 fatty acids is unclear. There are lots of contradictions in the literature with regard to the cytoprotective role of arachidonic acid. To date, there is no solid evidence that shows the protective role of omega-6 fatty acids in Parkinson's disease. In the current study, the potential of two omega-6 fatty acids (i.e. arachidonic acid and linoleic acid) in alleviating 1-methyl-4-phenylpyridinium (MPP+)-induced cytotoxicity in PC12 cells was examined. Methods: Cultured PC12 cells were either treated with MPP+ alone or co-treated with one of the omega-6 fatty acids for 1 day. Cell viability was then assessed by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: Cells treated with 500 mu M MPP+ for a day reduced cell viability to similar to 70% as compared to control group. Linoleic acid (50 and 100 mu M) significantly reduced MPP+-induced cell death back to similar to 85-90% of the control value. The protective effect could be mimicked by arachidonic acid, but not by ciglitazone. Conclusions: Both linoleic acid and arachidonic acid are able to inhibit MPP+-induced toxicity in PC12 cells. The protection is not mediated via peroxisome proliferator-activated receptor gamma (PPAR-gamma). Overall, the results suggest the potential role of omega-6 fatty acids in the treatment of Parkinson's disease.