Illite improves memory impairment and reduces A beta level in the Tg-APPswe/PS1dE9 mouse model of Alzheimer's disease through Akt/CREB and GSK-3 beta phosphorylation in the brain

Abstract

Ethnopharmacological relevance: The use of illite in Korean medicine has a long history as a therapeutic agent for various cerebrovascular diseases. According to Dongui Bogam, illite can be used for Qj-tonifying, phlegm dispersing and activation of blood circulation which is an important principle for the treatment of brain-associated diseases. Aim of the study: This study was undertaken to evaluate beneficial effects of illite on the neurodegenerative diseases such as Alzheimer's disease (AD). Material and methods: The transgenic mice of AD, Tg-APPswe/PS1dE9, were fed with 1% or 3% of illite for 3 months. Behavioral, immunological and ELISA analyses were used to assess memory impairment with additional measurement of A beta accumulation and plague deposition in the brain. Other in vitro studies were performed to examine whether illite inhibits the A beta-induced neurotoxicity in human neuroblastoma cell line, SH-SY5Y cells. Results: Illite treatment rescued A beta-induced neurotoxicity on SH-SY5Y cells, which was dependent on the PI3K/Alct activation. Intake of illite improved the A beta-induced memory impairment and suppressed A beta levels and plaque deposition in the brain of Tg-APPswe/PS1dE9 mice. Illite increased CREB, Akt, and GSK-3 beta phosphorylation and suppressed tau phosphorylation in the AD-like brains. Moreover, 1% of illite reduced weight gain and suppressed glucose level in the blood. Conclusion: The present study suggests that illite has the potential to be a useful adjunct as a therapeutic drug for the treatment of AD. (C) 2014 Elsevier Ireland Ltd. All rights reserved.