Treadmill exercise and wheel exercise enhance expressions of neutrophic factors in the hippocampus of lipopolysaccharide-injected rats

Brain inflammation plays a pivotal role in the pathogenesis of chronic neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. We investigated the effects of treadmill exercise and wheel exercise on spatial learning ability in relation with long-term potentiation (LTP) using lipopolysaccharide-induced brain inflammation in the rats. Brain inflammation was induced by an injection of LPS into the cerebral ventricle. We found that brain inflammation impaired spatial learning ability and suppressed the induction of LTP in the hippocampus, as well as weakening expressions of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (Trk-B) with the phosphorylated cyclic AMP response element binding protein (p-CREB). Both treadmill exercise and wheel exercise significantly improved spatial learning ability deteriorated by brain inflammation. These effects can be ascribed to the long-lasting effect of exercise on LTP through enhancement of the expressions regarding BDNF, TrkB, and p-CREB. Treadmill exercise and wheel exercise exerted similar effects on these factors. We infer that exercise may alleviate brain inflammation-induced learning impairment.

► Brain inflammation is implicated in the chronic neurodegenerative disorders.
► Brain inflammation in rats was induced by injection of LPS into cerebral ventricle.
► Brain inflammation impaired spatial learning ability and suppressed LTP.
► Treadmill exercise and wheel exercise alleviated LPS-induced learning impairment.
► Treadmill exercise and wheel exercise enhanced LTP in the LPS-injected rats.