Protective Effects Of Treadmill Exercise On aβ1-42-induced Inflammation And Cognitive Impairment In Rat

Abstract

Many studies suggest that regular exercise could reduce memory impairment, the main symptoms of Alzheimer's disease (AD), but the underlying mechanisms has not been elucidated. Inflammation incuded by β-amyloid (Aβ) deposition has been shown to play an critical role in AD pathogenesis. Increasing evidence show that aerobic exercise has anti-inflammatory and neuroprotective effects. We hypothesized that aerobic exercise could attenuates memory deficits by regulating inflammatory status. PURPOSE: To investigate whether regular aerobic exercise regulate inflammation and attenuate memory deficits induced by Aβ1-42 in rat. METHODS: Sprague-Dawley rats were divided into 3 groups: control group (C), Aβ1-42 infusion group (A), Aβ1-42 infusion with exercise group (E). Rats in group A and E were injected 10μg Aβ1-42 oligomer (1μg/μl saline) into their hippocampus, and rats from group C were injected with an same volume of saline. The rats in group E underwent aerobic exercise training on a leveled motorized treadmill at a moderate speed for consecutive 5 weeks (once a day, 6 days/week) starting at the 2nd day after Aβ1-42 injection. The memory ability was evaluated by Morris Water Maze (MWM) and the inflammatory status was analyzed by expressions levels of proinflammatory cytokines (TNF-α, IL-1β) and anti-inflammatory cytokine (TGF-β, IL-10) in hippocampus using Western Blot. RESULTS: MWM test showed that memory functions of rats were impaired by Aβ1-42 infusion, but this impairment was ameliorated by aerobic treadmill exercise. Compared with group C, both pro-inflammatory and anti-inflammatory cytokines in group A increased by different degrees (TNF-α: 306.9%, IL-1β: 255.6%, TGF-β: 78.3%, IL-10: 80.0%). Compared with group A, the expression of TNF-α and IL-1β in group AE decreased by 31.4% and 25.0%, whereas TGF-β and IL-10 increased by 68.5% and 39.0% respectively. CONCLUSIONS: The findings demonstrated that treadmill exercise could adjust inflammation status in hippocampus and attenuate the cognitive impairment of rats induced by Aβ1-42. Supported by the Fundamental Research Funds for the Central Universities,Southwest University for Nationalities (2018NQN19) and the Sichuan Science and Technology Project (18YYJC1355).