Chronic exposure to fluoxetine of female mice before mating causes impaired stress resilience in female offspring

Antidepressant agents have been proven their utilities in treating depression, but they also could serve as candidate drugs for misuse or abuse due to diverse pharmacologic properties. Potential detriments had also been multidimensionally investigated. However, there had been no study exploring whether treatment with antidepressants causes psychological and/or behavioral alterations in offspring. In this regard, we chronically treated normal female mice with different dosages (0, 10, and 20 mg/kg) of fluoxetine (FLU) for 2 weeks before mating them with drug-free male mice and then tested the offspring for anxiety/depression-like behaviors with the elevated plus maze and the tail-suspension test after exposing to acute or chronic stress in adult period. We found that there were significant increases for immobility time in the tail-suspension test as well as percentage of open arm entries and percentage of open arm time in the elevated plus maze test detected in the female offspring of the 20 mg group compared to both baseline and all other groups, with the exception that the female offspring of the 10 mg group showed an increased percentage of open arm entries after chronic stress exposure. Locomotor activity assessments showed that neither acute nor chronic stress protocol could significantly affect locomotor activities of mice. Conclusionally, we found that high-dosage FLU increased the risk of the female offspring developing into depression/anxiety-like behaviors after stress exposure, with chronic stress as the environmental-risk factor. Our study has important implications for the safe use of antidepressant agents and raises more concerns regarding long-term use of even second-generation antidepressants in clinical practice.