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

Epigenetic mechanisms in Alzheimer’s disease (AD) play a determining role in disease progression. To provide further insight on this matter, we evaluated whether early exposure of 5xFAD mice, a transgenic mouse model of AD, to either a standard, isolated or complex environment have a significant effect on the development of pathological hallmarks. Accordingly, we manipulated the animal environment with different housing conditions resulting in different cognitive and social stimuli. Amyloid plaques and gliosis were evaluated by immunohistochemistry at three months of age after two months of breeding under three different housing conditions. Our results demonstrated that both hallmarks were exacerbated in a complex environment and a slightly less so in an isolated condition, compared with a standard social housing condition. Unexpectedly, an enriched environment with high behavioural stimulation can exacerbate the progression of the disease at least in the early stages. These data cast doubt on the general assumption that an enriched environment conveys beneficial effects on disease progression and suggest that strong environmental stimuli may be counterproductive, at least in the early stages of the pathology.