Protective Effect of Recombinant Ganoderma Lucidum Immunomodulatory Protein (rLZ-8) Against Scopolamine-Induced Alzheimer's Disease in Rats

Backgroud: Alzheimer's disease (AD) is one of the most common neurodegenerative diseases in the elderly, seriously threatening the health of the elderly. In this study, the protective effect of recombinant Ganoderma lucidum immunomodulatory protein (rLZ-8) against the scopolamine-induced Alzheimer's disease (AD) in rats was studied for the first time. Methods: Male Wistar rats in rLZ-8-treated groups were intraperitoneally injected with 56 μg/kg, 112 μg/kg, and 224 μg/kg rLZ-8, respectively, those in donepezil group were intraperitoneally injected with 1.0mg/kg donepezil, and those in the normal saline group were intraperitoneally injected with an equal volume of normal saline, successively for 14 days. On the 7th day after the administration, the learning and memory ability of rats was observed by Morris water maze test, and the biochemical indexes and cytokines in the serum and brain tissues of the rats were detected after the behaviour test for investigating the protective mechanism of rLZ-8 against the scopolamine-induced AD in rats. Results: In the water maze test, compared with that in the model group, the escape latency and the swimming distance of rats on the 5th and 6th day were significantly shortened in the three rLZ-8-treated groups. In the space exploration test, compared with that in the model group, the number of passing through the location of original platform was significantly increased and the time of rats’ staying in the second quadrant was significantly prolonged in the three rLZ-8-treated groups, and furthermore, the detectionresults related to Alzheimer's disease in the serum, hippocampus and cerebral cortex of ratsindicated that rLZ-8 could improve the contents or activities of the related indexes. Conclusion: In rlZ-8 could significantly improve the learning and memory ability of AD rats, and the possible mechanism was to improve the learning and memory ability by protecting the cholinergic system.