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

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 Qi-tonifying, phlegm dispersing and activation of blood circulation which is an important principle for the treatment of brainassociated 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 Aβ accumulation and plaque deposition in the brain. Other in vitro studies were performed to examine whether illite inhibits the Ainnodatabeta-induced neurotoxicity in human neuroblastoma cell line, SH-SY5Y cells. Results: Illite treatment rescued Aβ-induced neurotoxicity on SH-SY5Y cells, which was dependent on the PI3K/Akt activation. Intake of illite improved the Aβ-induced memory impairment and suppressed Aβ levels and plaque deposition in the brain of Tg-APPswe/PS1dE9 mice. Illite increased CREB, Akt, and GSK-3β 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.