Serum glutathione peroxidase, xanthine oxidase, and superoxide dismutase activities and malondialdehyde levels in patients with Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). Oxidative stress has been hypothesized to play a major role in the development of PD in various studies. This study assessed to investigate oxidative and anti-oxidative status in PD patients. We evaluated oxidant/antioxidant status by measuring serum malondialdehyde (MDA) levels, xanthine oxidase (XO) activities, and activities of antioxidant enzymes, namely, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). The study included 29 patients with PD and 32 healthy subjects as controls. Comparison of oxidative parameters in the patient and control groups revealed significantly higher GSH-Px and XO activities in the patient group. Serum MDA and SOD activities in PD patients were not significantly different from the controls. MDA was negatively correlated with duration of the PD and positively with age of onset. There was a negative correlation between SOD and Hoehn and Yahr (H&Y) stage. According to these results, we suggest that oxidative stress may contribute to the development of PD.