Electroacupuncture improves cognitive deficits and insulin resistance in an OLETF rat model of Al/D-gal induced aging model via the PI3K/Akt signaling pathway

Abstract

To investigate the effect of electroacupuncture (EA) on cognitive function and insulin resistance (IR) in an Al/D-gal-induced aging model for Alzheimer’s disease (AD) using Ostuka Long-Evans Tokushima Fatty (OLETF) rats. The Al/D-gal-OLETF rats for AD were randomly divided into the EA and non-EA groups. Cognitive function was assessed using the Morris water maze (MWM). The morphology of the hippocampal neurons was observed using hematoxylin & eosin (H&E) staining. Aβ and total Tau in the hippocampus and cerebrospinal fluid (CSF) were detected using western blotting (WB) and enzyme-linked immunosorbent assay (ELISA). Fasting blood glucose (FPG) was determined using the glucose oxidase method. Plasma fasting insulin (FINS), serum C-peptide (C-P), and CSF insulin were detected using ELISA. The expression of the genes and proteins in the PI3K signaling pathway was detected using quantitative real-time PCR and WB. After EA intervention, the hippocampal Aβ and total Tau protein levels, body weight, FPG, FINS, and C-P were significantly decreased. The MWM showed that the percentage of time in the target quadrant of the EA group was elevated in the probe test. The protein levels of p-IRS1, p-IRS2, IDE, and p-GSK3β were significantly increased, while p-PI3K-p85α and p-Akt were decreased. In conclusion, EA improves cognitive function and insulin resistance in rat models of AD. The PI3K/Akt signaling pathway is involved in those changes.