Neuroprotective Effect of EGb761® and Low-dose Whole-body γ-irradiation in a Rat Model of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. The present study was undertaken to investigate the pretreatment effects of standardized Ginkgo biloba extract (EGb761(®)) and low-dose whole-body γ-irradiation on the neurological dysfunction in the reserpine model of PD. Male Wistar rats were pretreated orally with EGb761 or fractionated low-dose whole-body γ-irradiation or their combination, then subjected to intraperitoneal injection of reserpine (5 mg/kg body weight) 24 h after the final dose of EGb761 or radiation. Reserpine injection resulted in the depletion of striatal dopamine (DA) level, increased catalepsy score, increased oxidative stress indicated via depletion of glutathione (GSH), increased malondialdehyde (MDA) and iron levels, decreased DA metabolites metabolizing enzymes; indicated by inhibition by glutathione-S-transferase, and nicotinamide adenine dinucleotide phosphate (NADPH)-quinone oxidoreductase (NQO) activities, mitochondrial dysfunction; indicated by declined complex I activity, and adenosine triphosphate (ATP) level and increased apoptosis; indicated by decreased mitochondrial B cell lymphoma-2 (Bcl-2) protein level and by transmission electron microscope. EGb761 and low-dose γ-radiation ameliorated the reserpine-induced state of oxidative stress, mitochondrial dysfunction, and apoptosis in brain. It can be concluded that EGb761, a widely used herbal medicine and low dose of γ-irradiation have protective effects for combating Parkinsonism possibly via replenishment of GSH levels.