Effects of uric acid on learning and memory ability of rats with of Parkinson disease and the mechanism

Abstract

Objective To investigate the effects of uric acid upon learning and memory ability of Sprague-Dawley(SD) rats with Parkinson disease (PD) induced by 6-OHDA and the mechanism. Methods Female SD rats were divided into control group (group A), PD group (group B), PD uric acid treatment group (group C1-C5) (n=15 each). During the 1st to 6th day the rats in groups CI-C.5 were intraperitone-ally injected with 0.1, 1,5, 10.0, 20.0 mg/(kg·d) uric acid, and those in groups A, and B were intraperitoneally injected with equal doses of normal saline. At the third week, the rats in each group were subjected to Y-type electric maze test. At the fourth week all rats were decapitated. Malondialdehyde (MDA) content in striatum was measured by using spectrophotometer, and tyrosine hydroxylase (TH) and Caspase-3-positive neurons in substantia nigra were identified by immunohistochemistry. Results Average learning achievement in group A was (4.12±1.57) times, and memory performance was (3.17±1.19) times. As compared with group A, learning and memory ability in group B and groups C1-C5 was decreased significantly (P 0.01). There was significant difference between groups C2, C3 and groups C1, C4, C5 (P<0.01). Conclusion Learning and memory ability in PD rats was significantly decreased, while appropriate doses of uric acid can improve the PD learning and memory ability, which may be related to its neuroprotective property by reducing the oxidative stress to decrease dopaminergic neuronal apoptosis, thus to protect the dopaminergic neurons. Key words: Parkinson's disease; Uric acid; 6-OHDA; Dopaminergic neurons