Erythropoietin modulates striatal antioxidant signalling to reduce neurodegeneration in a toxicant model of Parkinson's disease

Abstract

The current study sought to characterize the pro-survival effects of erythropoietin (EPO) in a toxicant model of Parkinson's disease (PD). EPO treatment induced time-dependent elevations of antioxidant glutathione peroxidase (GPx) and anti-apoptotic factors (pAkt and pBad/Bad) within the striatum and substantia nigra pars compacta (SNc). Intriguingly, our results indicated a region- and lesion size- dependence of pro-survival effects of EPO. Indeed, intra-striatal (but not intra-nigral) infusion of EPO was effective at preventing dopaminergic terminal degeneration and sSNc neuronal loss induced by two different doses of 6-OHDA. These neuroprotective consequences were paralleled by a diminution of microglial morphological changes, along with enhanced motor functioning seen through a reduction in apomorphine-induced rotational behaviour. Finally, in the context of the 6-OHDA lesion, EPO again induced anti-apoptotic (Bcl-2) and antioxidant (GPx) factors within the striatum. Taken together, these results raise the possibility of EPO's potential use as an adjuvant therapy in the treatment of PD, or at least, suggest possible brain-region specific targets for the protective effects of EPO.