Neuroprotective effect of silymarin in 6-hydroxydopamine hemi-parkinsonian rat: Involvement of estrogen receptors and oxidative stress

This study examined neuroprotective effect of silymarin (SM) in a model of Parkinson's disease (PD). Unilateral intrastriatal 6-hydroxydopamine (6-OHDA)-lesioned rats were pretreated i.p. with SM (100 and 200 mg/kg) 1 h before neurotoxin injection. Fulvestrant was used to evaluate the involvement of estrogen receptors. Net apomorphine-induced rotations and number of Nissl-stained neurons of substantia nigra pars compacta (SNC) were counted in addition to measurement of oxidative stress markers. SM administration only at a dose of 200 mg/kg attenuated the rotational behavior in 6-OHDA-lesioned rats and protected the neurons of SNC against its toxicity and fulvestrant partially attenuated this beneficial effect of SM. In addition, pretreatment with SM at a dose of 200 mg/kg significantly decreased the 6-OHDA-induced thiobarbituric acid reactive substances (TBARS) formation. SM exhibits a dose-dependent neuroprotective effect against 6-OHDA toxicity, partly through attenuating oxidative stress and via an estrogenic pathway.