troxerutin and Memory-Disorders

Alzheimer׳s disease (AD) is a neurodegenerative disorder with a progressive cognitive decline and memory loss. Multiple pathogenetic factors including aggregated β-amyloid (Aβ), neurofibrillary tangles (NFTs), cholinergic dysfunction and oxidative stress are involved in AD. Aβ, a major constituent of the senile plaques, is a potent neurotoxic peptide and has a pivotal role in cognitive deficit and reduced synaptic plasticity in AD. In the present study we examined the protective effect of troxerutin, as a multipotent bioflavonoid, on Aβ (1-42)-induced impairment of evoked field potential in hippocampal DG neurons. Male Wistar rats were divided into four groups including Aβ (42-1), Aβ (1-42), Aβ (1-42) plus troxerutin and Aβ (42-1) plus troxerutin groups. Aβ was injected intracerebroventricularly (i.c.v.) into right lateral ventricle and after two weeks the evoked field potential recorded from perforant path-DG synapses to assess paired pulse paradigm and long term potentiation (LTP). Administration of Aβ (1-42) drastically attenuated the LTP of DG neurons, while there was no significant difference in evoked field potentials between Aβ (1-42) plus troxerutin group with respect to Aβ (42-1) group. This study revealed that troxerutin improves the synaptic failure induced by Aβ peptide and can be introduced as a promising multi-potent pharmacological agent in prevention or treatment of AD in the future.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Dentate Gyrus; Electrophysiological Phenomena; Hydroxyethylrutoside; Long-Term Potentiation; Male; Maze Learning; Memory Disorders; Neuronal Plasticity; Neuroprotective Agents; Rats; Rats, Wistar; Synapses

The C/EBP β is a basic leucine zipper transcription factor that regulates a variety of biological processes, including metabolism, cell proliferation and differentiation, and immune response. Recent findings show that C/EBP β-induced inflammatory responses mediate kainic acid-triggered excitotoxic brain injury. In this article, we show that protein kinase C ζ enhances K-ras expression and subsequently activates the Raf/MEK/ERK1/2 pathway in the hippocampus of domoic acid (DA)-treated mice, which promotes C/EBP β expression and induces inflammatory responses. Elevated production of TNF-α impairs mitochondrial function and increases the levels of reactive oxygen species by IκB kinase β/NF-κB signaling. The aforementioned inflammation and oxidative stress lead to memory deficits in DA-treated mice. However, troxerutin inhibits cyclin-dependent kinase 1 expression, enhances type 1 protein phosphatase α dephosphorylation, and abolishes MEK/ERK1/2/C/EBP β activation, which subsequently reverses the memory impairment observed in the DA-treated mice. Thus, troxerutin is recommended as a potential candidate for the prevention and therapeutic treatment of cognitive deficits resulting from excitotoxic brain damage and other brain disorders.

Topics: Animals; Butadienes; CCAAT-Enhancer-Binding Protein-beta; CDC2 Protein Kinase; Gene Knockdown Techniques; Genes, ras; Hippocampus; Hydroxyethylrutoside; Inflammation; Inflammation Mediators; Kainic Acid; Male; Memory Disorders; Mice; Mitochondria; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; NADPH Oxidases; Nitriles; Oxidative Stress; Phosphoprotein Phosphatases; Phosphorylation; Protein Kinase C; Reactive Oxygen Species; Signal Transduction