Study of behavioural, molecular, morphological and electrophysiological effects of chronic stress in mice

Chronic stress profoundly affects brain function and represents a major risk factor for psychiatric and systemic disorders. Understanding its impact requires an integrated view that links behavioural, molecular, and neural mechanisms. Biological variables such as sex and circadian timing may shape stress responses, but how these factors interact with the underlying synaptic and functional changes remains unclear. This study investigates how chronic stress alters behaviour, hippocampal proteome composition, neuronal morphology, and brain activity, considering the modulatory influence of sex and circadian phase. Male and female C57BL/6 mice were exposed to a Chronic Restraint Stress (CRS) paradigm (2 h/day for 21 days) during either the light or dark phase. Behavioural tests assessed depressive-, anxiety-, and anhedonia-like phenotypes. Based on behavioral readouts, we selected female mice for further functional, structural, and molecular studies. EEG recordings throughout the CRS protocol were used to assess stress-induced alterations in neural activity during emotional and cognitive tasks. Hippocampal dendritic architecture has been evaluated using Golgi-Cox staining, while hippocampal synaptic fractions have undergone proteomic profiling to identify synaptic molecular pathways affected by stress. We found a higher behavioral sensitivity to stress in female mice. Proteomic analyses identified stress-induced modulation of synaptic proteins, while morphological and electrophysiological investigations are expected to further clarify how chronic stress reshapes neuronal connectivity and activity dynamics. By combining behavioural, proteomic, morphological, and functional approaches, this study provides an innovative integrated perspective on how chronic stress impacts on the brain. The results highlight the complex interplay among biological variables and molecular networks, offering new insights into mechanisms of stress in the brain.