Effects of chronic stress and antidepressant treatment on behavioral, physiological and neurochemical aspects in male and female rats

Background: Although the etiology of clinical depression is unknown, women are more likely to suffer from major depressive disorder than men. The biological basis of gender differences in stress response and recovery still remain poorly understood. Objectives: The aim of the present study was to investigate the gender specific behavioral, physiological and neurochemical aspects of rats exposed to chronic stress paradigm along with the recovery using antidepressant drug treatment in rats using Learned Helplessness (LH) model of depression. Methods: Stress induction was applied on rats through inescapable footshocks and subsequent shuttle-box escape test. Fluoxetine hydrochloride as antidepressant drug was used for recovery. Body weight and adrenal gland weight were measured. BDNF (Brain derived neurotrophic factor) level in hippocampus was measured by sandwich ELISA. Estrous stages in female rats were also examined. Results: Rats of both sexes exhibited marked alteration in BDNF level, body weight and adrenal weight along with their escape latency. After antidepressant drug treatment restoration of normal behavior was also observed. In estrous cycle analysis the depressed female rats exhibited significant variations. Conclusion: Depressogenic effect favors females with prolonged persistence of estrus phase, significant enlargement of adrenal glands and significant reduction of BDNF levels in hippocampus.