Electroacupuncture improves cognitive deficits and activates PPAR-γ in a rat model of Alzheimer's disease

Alzheimer's disease (AD) is an age-associated neurodegenerative disorder that is associated with a progressive impairment of cognition. Acupuncture has protective effects, although the molecular mechanisms are largely unknown. The activation of peroxisome proliferator activated receptor γ (PPAR-γ) has an impact on the pathogenesis of AD.

To test the hypothesis that electroacupuncture (EA) confers therapeutic benefits through activation of PPAR-γ in a rat model of AD.

80 male Sprague-Dawley rats were randomly divided into four groups (n=20 each): Control (healthy control group), Sham (sham-operated group), AD (untreated AD model group), and AD+EA (AD model group treated with EA). The AD model was induced in the latter two groups by injection of amyloid-β (Aβ)1-40 into the hippocampal CA1 area bilaterally. EA was administered at GV20 and BL23 six times per week for 4 weeks. The rats' behaviour was examined using the Morris water maze test, and protein expression of Aβ, hyperphosphorylated tau protein (p-Tau), PPAR-γ, and hyperphosphorylated p38 mitogen activated protein kinase (p38MAPK) in the hippocampal CA1 region was examined by immunohistochemistry and Western blotting.

EA significantly improved cognitive deficits and reduced Aβ and p-Tau Ser404 protein concentrations in the hippocampal CA1 region. AD decreased PPAR-γ and increased p-p38MAPK, while EA significantly upregulated PPAR-γ expression and significantly downregulated p-p38MAPK expression.

Acupuncture at GV20 and BL23 might have a beneficial effect on rats with AD via activation of PPAR-γ and inhibition of p-p38MAPK expression.