Early-Life Ventral Hippocampal Lesion and Circadian Disruption Result in Altered Behavior in Adult Mice in a Sex-Dependent Manner.

Schizophrenia is believed to arise because of the interaction of early abnormal neurodevelopment with environmental insults during key developmental stages later in life. Furthermore, disrupted circadian rhythms are reported in patients, and circadian disruption is associated with increased symptom severity, hinting at its role as a risk factor. Using the neonatal ventral hippocampal lesion mouse model, we aimed to assess the interaction between disrupted ventral hippocampal development with circadian disruption during adolescence in affecting behavior in male and female C57BL/6N mice. After conducting a series of behavioral tests, we found that the neonatal ventral hippocampal lesion and chronic jet lag during adolescence synergistically led to increased anxiety-like behavior in males. In females, the lesion prevented increased social preference caused by chronic jet lag and led to increased anxiety-like behavior. Mice were then moved to running wheel cages to measure their locomotor activity rhythms. We found that the lesioned male mice exposed to chronic jet lag exhibited fragmented rhythms under constant darkness. Moreover, lesioned male and female mice, especially those exposed to chronic jet lag, had reduced activity counts under constant light. These findings highlight that the interaction of abnormal neurodevelopment in areas relevant to schizophrenia with circadian disruption during adolescence results in lasting behavioral changes in a sex-dependent manner in mice.