Effects of (-)-epicatechin on neuroinflammation and hyperphosphorylation of tau in the hippocampus of aged mice

Food Funct. 2020 Dec 1;11(12):10351-10361. doi: 10.1039/d0fo02438d. Epub 2020 Nov 17.

Abstract

Evidence has implicated oxidative stress (OS) and inflammation as drivers of neurodegenerative pathologies. We previously reported on the beneficial effects of (-)-epicatechin (Epi) treatment on aging-induced OS and its capacity to restore modulators of mitochondrial biogenesis in the prefrontal cortex of 26-month-old male mice. In the present study using the same mouse model of aging, we examined the capacity of Epi to mitigate hippocampus OS, inflammation, hyperphosphorylation of tau protein, soluble β-amyloid protein levels, cell survival, memory, anxiety-like behavior levels and systemic inflammation. Mice were subjected to 4 weeks of Epi treatment (1 mg kg-1 day-1) and samples of the hippocampus were obtained. Assessments of the OS markers, protein carbonyls, and malondialdehyde levels demonstrated their significant increase (∼3 fold) with aging that were partially suppressed by Epi. The protein levels of the glial fibrillary acidic protein, inflammatory factor 1 (Iba1), pro-inflammatory cytokines, interleukins (IL-1β, IL-3, 5, 6 and 15), cyclooxygenase 2, tumor necrosis factor α, nuclear factor-activated B cells and interferon γ increase with aging and were also significantly decreased with Epi treatment. However, anti-inflammatory cytokines, IL-1ra, IL-10 and 11 decrease with aging and were restored with Epi. Epi also reversed the aging effects on the hyperphosphorylation of tau, increased soluble β-amyloid levels (∼2 fold), cellular death (as per caspase 3 and 9 activity), and reduced nerve growth factor and triggering receptor expressed on myeloid cells 2 levels. Measures of anxiety like-behavior and memory demonstrated improvements with Epi treatment. Indicators of systemic inflammation increase with aging and Epi was capable of decreasing blood inflammatory markers. Altogether, the results show a significant capacity of Epi to mitigate hippocampus OS and inflammation leading to improved brain function.

MeSH terms

  • Aging / drug effects
  • Amyloid beta-Peptides / metabolism
  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Catechin / pharmacology*
  • Cytokines / metabolism
  • Glial Fibrillary Acidic Protein / metabolism
  • Hippocampus / metabolism*
  • Inflammation / drug therapy*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Oxidative Stress / drug effects*
  • Phosphorylation
  • tau Proteins / metabolism*

Substances

  • Amyloid beta-Peptides
  • Anti-Inflammatory Agents
  • Cytokines
  • Glial Fibrillary Acidic Protein
  • tau Proteins
  • Catechin