Green tea polyphenols protect against okadaic acid-induced acute learning and memory impairments in rats

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Vol. 30; no. 3; pp. 337 - 342
• Main Authors: Li, Hongyu, Ph.D, Wu, Xiukui, M.Sc, Wu, Qiong, Ph.D, Gong, Dezheng, M.Sc, Shi, Meijun, M.Sc, Guan, Lili, Ph.D, Zhang, Jun, M.D, Liu, Jing, Ph.D, Yuan, Bo, M.Sc, Han, Guozhu, M.Sc, Zou, Yuan, Ph.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.03.2014; Elsevier; Elsevier Limited
• Subjects: Acquisitions & mergers; Alzheimer Disease; Alzheimer's disease; Animals; Antioxidants - pharmacology; Biological and medical sciences; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; Green tea; Green tea polyphenols; Hippocampus - drug effects; Hippocampus - metabolism; Hyperphosphorylation; Laboratory animals; Learning - drug effects; Maze Learning; Memory; Memory Disorders - chemically induced; Memory Disorders - drug therapy; Neuroprotection; Neuroprotective Agents - pharmacology; Neurotoxicity; Okadaic acid; Okadaic Acid - administration & dosage; Okadaic Acid - adverse effects; Phosphatase; Phosphorylation; Phosphorylation - drug effects; Polyphenols; Polyphenols - pharmacology; Proteins; Rats; Rats, Sprague-Dawley; Rodents; Studies; Swimming; Tau protein; tau Proteins - genetics; tau Proteins - metabolism; Tea - chemistry; Vertebrates: anatomy and physiology, studies on body, several organs or systems; China; Green tea polyphenols; Hyperphosphorylation; Neuroprotection; Okadaic acid; Tau protein; Memory disorder; Cognitive disorder; Nutrition; Rat; Acute; Rodentia; Micronutrient; Learning; Vertebrata; Polyphenol; Mammalia; Acquisition process; Animal; Proanthocyanidin; Green tea
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/j.nut.2013.08.021

Abstract Objective Green tea polyphenols (GTPs) are now being considered possible protective agents in neurodegenerative diseases such as Alzheimer's disease (AD). Previous studies suggested that GTPs could inhibit amyloid fibril formation and protect neurons from toxicity induced by β-amyloid. However, whether GTPs can ameliorate learning and memory impairments and also reduce tau hyperphosphorylation induced by okadaic acid (OA) in rats remains unclear. The aim of this study was to determine if GTPs have neuroprotection against OA-induced neurotoxicity. Methods In this work, rats were pretreated with GTPs by intragastric administration for 4 wk. Then OA was microinjected into the right dorsal hippocampus. Morris water maze tests were used to test the ethologic changes in all groups, and tau protein hyperphosphorylation was detected both in vivo and in vitro. Results The ethologic test indicated that the staying time and swimming distance in the target quadrant were significantly decreased after OA treatment, whereas rats pretreated with GTPs stayed longer in the target quadrant. Methyl thiazolyl tetrazolium assay and lactate dehydrogenase leakage showed that GTPs greatly ameliorated primary hippocampal neurons damage induced by OA. Furthermore, reduced hyperphosphorylated tau protein was detected with GTPs pretreatment. Conclusion Taken together, our results suggest that GTPs have neuroprotection against OA-induced neurotoxicity.