Persistent exercise fatigue and associative learning deficits in combination with transient glucose dyshomeostasis in a mouse model of Gulf War Illness

Life Sci. 2022 Jan 15:289:120094. doi: 10.1016/j.lfs.2021.120094. Epub 2021 Oct 26.

Abstract

Aims: To characterize exercise fatigue, metabolic phenotype and cognitive and mood deficits correlated with brain neuroinflammatory and gut microbiome changes in a chronic Gulf War Illness (GWI) mouse model. The latter have been described in an accompanying paper [1].

Main methods: Adult male C57Bl/6N mice were exposed for 28 days (5 days/week) to pyridostigmine bromide: 6.5 mg/kg, b.i.d., P.O. (GW1) or 8.7 mg/kg, q.d., P.O. (GW2); topical permethrin (1.3 mg/kg in 100% DMSO) and N,N-diethyl-meta-toluamide (DEET 33% in 70% EtOH) and restraint stress (5 min). Exercise, metabolic and behavioral endpoints were compared to sham stress control (CON/S).

Key findings: Relative to CON/S, GW2 presented persistent exercise intolerance (through post-treatment (PT) day 161), deficient associative learning/memory, and transient insulin insensitivity. In contrast to GW2, GW1 showed deficient long-term object recognition memory, milder associative learning/memory deficit, and behavioral despair.

Significance: Our findings demonstrate that GW chemicals dose-dependently determine the presentation of exercise fatigue and severity/type of cognitive/mood-deficient phenotypes that show persistence. Our comprehensive mouse model of GWI recapitulates the major multiple symptom domains characterizing GWI, including fatigue and cognitive impairment that can be used to more efficiently develop diagnostic tests and curative treatments for ill Gulf War veterans.

Keywords: Central nervous system; Cognitive impairment; Depression; Diabetes; Insulin insensitivity; Mood; Novel object recognition memory; Passive avoidance learning.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Fatigue* / chemically induced
  • Fatigue* / metabolism
  • Fatigue* / pathology
  • Glucose / metabolism*
  • Humans
  • Learning Disabilities* / chemically induced
  • Learning Disabilities* / metabolism
  • Learning Disabilities* / pathology
  • Male
  • Mice
  • Persian Gulf Syndrome* / chemically induced
  • Persian Gulf Syndrome* / metabolism
  • Persian Gulf Syndrome* / pathology
  • Pyridostigmine Bromide / adverse effects*
  • Pyridostigmine Bromide / pharmacology

Substances

  • Glucose
  • Pyridostigmine Bromide