These results are in line with those observed by Wang et al. 2006 who showed Cr(VI) given orally to mice induces hepatocytes apoptosis (Wang et al. 2006). These results suggest that in the brain tissue the activation of Nrf2 is an adaptive intracellular response to PD-induced oxidative stress and that Nrf2 is protective against PD-induced apoptosis. This evidence concerns the gene NFE2L2 and Parkinson disease.