Vegetation structure shapes behavioral, neuroimmune and gut microbial recovery after chronic stress in mice

Chronic stress impairs behavior, neuroimmune regulation and gut microbial ecology, but whether natural-environment structure shapes recovery remains unclear. Here, we tested whether landscape design, beyond greenness alone, promotes recovery in chronically stressed male mice. During a 28-day recovery phase, mice were exposed to five parameterized vegetated landscapes differing in openness, canopy density and visual complexity, a matched urban-gray setting, or standard housing. Vegetated exposure improved anxiety-like behavior, behavioral despair and anhedonia, whereas the gray setting showed little benefit. Recovery was design-dependent: multistrata, color-rich landscapes produced the fastest and most sustained behavioral improvement, while open lawn-dominant layouts showed weaker, partly transient effects. These gains were accompanied by lower interleukin-1β and interleukin-6, normalized hippocampal Iba-1, preserved brain-derived neurotrophic factor, and restored gut microbial diversity. Predicted microbial functions linked butyrate-related pathways with neuroimmune-behavioral indices. These findings support vegetation structure as a tunable environmental variable for coordinated recovery after chronic stress.