Epigallocatechin-3-Gallate Provides Protection Against Alzheimer's Disease-Induced Learning and Memory Impairments in Rats

Purpose: Recent evidence has highlighted the anti-inflammatory properties of the constituent of Green Tea Polyphenols (GTP), epigallocatechin-3-gallate (EGCG) which has been suggested to exert a neuroprotective effect on Alzheimer's disease (AD). The current study aimed to elucidate the effect of EGCG on memory function in rats with AD. Methods: AD rat models were initially established through an injection with A beta 25-35 solution, followed by gavage with EGCG at varying doses to determine the effect of EGCG on learning and cognitive deficits in AD. Morris water maze test was conducted to evaluate the spatial memory function of the rats. Immunohistochemistry and Western blot analysis were performed to identify Tau phosphorylation. The expression of beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1) mRNA and protein in rat hippocampus was measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis. Acetylcholinesterase (AchE) activity, A beta 1-42 expression and Ach content were all detected using enzyme-linked immunosorbent assay (ELISA). Results: EGCG intervention brought about a decrease in the escape latency period while increasing the time at the target quadrant among the AD rats. EGCG decreased the hyperphosphorylation of Tau in hippocampus. BACE1 expression and activity as well as the expression of A beta 1-42 were suppressed by EGCG. Moreover, EGCG promoted Ach content by diminishing the activity of AchE. Conclusion: The current study demonstrates that EGCG may diminish the hyperphosphorylation of the Tau protein, downregulate BACE1 and A beta 1-42 expression to improve the antioxidant system and learning and memory function of rats with AD.

Automated summary

Recent evidence suggests that EGCG, a constituent of Green Tea Polyphenols, may have anti-inflammatory properties and exert a neuroprotective effect on Alzheimer's disease. In AD rat models, EGCG intervention decreased escape latency period, decreased Tau hyperphosphorylation, suppressed BACE1 expression and A beta 1-42 expression, and promoted Ach content by diminishing AchE activity. These findings suggest that EGCG may improve the antioxidant system and learning and memory function in rats with AD.