Modeling Gulf War Illness: anxiety, memory deficits, cholinergic and potassium channel imbalance in male and female mice.

Gulf War Illness (GWI) is a complex, multisystem condition that remains difficult to diagnose, with an etiology thought to involve interactions between stress and exposure to acetylcholinesterase (AChE) inhibitors of varying potency. Although rodent models using GWI-related neurotoxicants have been developed, many do not fully replicate war-theater conditions, particularly the inclusion of sarin exposure. We modeled a GW-like exposure in male and female C57BL/6J mice using pyridostigmine bromide (PB), permethrin (PER), N,N-diethyl-meta-toluamide (DEET), moderate stress, and Diisopropylfluorophosphate (DFP), a sarin analog. GW-like exposure initiated early symptoms of anxiety-like behavior and disrupted hippocampal-dependent spatial learning and memory retrieval across the studied cohorts. Short-term recognition memory deficits were observed in both sexes, while long-term memory impairment was limited to females. To investigate the biological basis of the observed behavioral deficits, we performed complementary analyses. In males, western blot analysis revealed a > 50% reduction in nicotinic receptor (α4β2 AChR) and potassium ion channels (Kv2.2 and Kir7.1) expression, suggesting compromised cholinergic modulation of neuronal excitability. In females, muscarinic receptor (M1R) expression was reduced by more than 25%, and choline acetyltransferase (ChAT) levels were elevated, suggesting a sex-specific compensatory mechanism to maintain cholinergic tone in the absence of changes in AChE. Neuroinflammatory analysis revealed a 37% increase in GFAP protein expression in GWI females, indicating chronic astrocyte activation. Proteomics analysis supported the presence of sex-dependent neurobiological alterations, with both sexes showing disruptions in proteins involved in neuronal signaling and mitochondrial metabolism, yet involving distinct molecular signatures. These findings underscore the sexually dimorphic nature of GWI pathophysiology.