Neuroprotective Effects of Ellagic Acid in a Rat Model of Parkinson's Disease

Abstract

Antioxidants have protective effects against free radicals-induced neural damage in Parkinson's disease (PD). We examined the effects of ellagic acid (EA) on locomotion, pallidal local EEG, and its frequency bands' power and also cerebral antioxidant contents in a rat model of PD induced by 6-hydroxidopamine (6-OHDA). 6-OHDA (16 µg/2µ l) was injected into the right medial forebrain bundle (MFB) in MFB-lesioned rat's brain. Sham group received vehicle instead of 6-OHDA. PD-model was confirmed by rotational test using apomorphine injection. EA (50 mg/kg/2 ml, by gavages) was administered in PD+EA group. One group of MFB-lesioned rats received pramipexole (PPX; 2 mg/kg/2 ml, by gavages) as a positive control group (PD+PPX group). Motor activity was assessed by stride length, rotarod, and cylinder tests. Pallidal local EEG was recorded in freely moving rats. The levels of malondialdehyde (MDA) besides Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were measured in both striatum and hippocampus tissues. MFB lesion caused significant reduction of stride-length (P<0.001), bar decent latency (P<0.001) and frequency bands' power of pallidal EEG (P<0.001). Use of 6-OHDA caused a reduction in the GPx (P<0.001) and SOD (P<0.001) activities while increased significantly the levels of MDA (P<0.001) in MFB-lesioned rats. EA significantly restored all above parameters. The results show that EA can improve the motor impairments and electrophysiological performance in the MFB-lesioned rats via raising the cerebral antioxidant contents. Therefore, EA can protect the brain against free radicals-induced neural damage and may be beneficial in the treatment of PD.

Keywords

• Parkinson's disease
• Ellagic acid
• Locomotion
• EEG
• Antioxidants