Early Amyloid-β Deposits and Astrogliosis AreModulated by Housing Conditions in 5xFAD Mice

Epigenetic mechanisms in Alzheimer’s disease (AD) play a determining role in disease progression. To provided further insight on this matter, we evaluated whether early exposure of 5xFAD mice to either a standard, isolated or complex environment have a significant effect on the development of pathological hallmarks in this transgenic mouse model of AD. Accordingly, we manipulated the animal environment with different housing conditions that result in different cognitive and social stimuli. One month after birth followed by two months breeding under three different housing conditions, amyloid plaques and gliosis were evaluated. Our results demonstrated that both hallmarks were exacerbated in a complex environment and a bit less in isolated condition, in comparison with a standard social condition of housing. Thus, unexpectedly, an enriched environment conveying high behavioral stimulation can exacerbate the progression of the disease at least in the early stages. These data casts doubt on the general assumption that an enriched environment conveys beneficial effects on disease progression and suggest that strong environmental stimuli can be counterproductive, at least at the early stages of the pathology.