GENDER RELATED DIFFERENCES IN SEX HORMONE-MEDIATED ANXIOLYTIC EFFECTS OF ELECTROMAGNETIC STIMULATION DURING IMMOBILIZATION STRESS

Physical and psychological stressors activate the hypothalamic-pituitary-adrenal axis (HPA). Elevated glucocorticoid levels over a long time harm neurocognitive and neurobiological development and cause deleterious effects. The effects of glucocorticoids depend not only on the concentration and duration of action, but also on the period of life when the effect occurs and gender. Electromagnetic stimulation (EMS) is a non-invasive treatment for some neurodegenerative diseases. The main objective of the study was to investigate the therapeutic effects of EMS on immobilization-induced depressive behavior (moderate stress) depending on sex hormones in an open field test. Experiments were conducted on rats both gender (n=36, 4-6 months old, 190- 220 g). The rats were group-housed in standard box cages (12-hour light-dark cycle, food and water were available ad libitum). Female and male rats were divided into 2 groups: intact and gonadectomized (n=9 in each group). Six rats from each group were immobilized 2 hours a day during 10 days. Effects of EMS were studied in all group of rats. For EMS, the following parameters were used: 15000 Hz frequency, 1,5 m/Tesla, during 20 min, 10 days. Parameters of psycho-emotional behaviour was studied in the Open - field test. Data reliability was assessed using parametric and non-parametric techniques, with the use of one- and two- way layout of factorial analysis (ANOVA). Chronic immobilization for 10 days reduced the motor-exploratory activity in male rats compared to females. EMS restored data to baseline in female but not male rats. Intact male rats had a high number of vertical stands than females. Immobilization stress significantly reduced these data in male rats compared to females. Repeated EMS within 10 days reduced the vertical stands to zero. In gonadectomized rats, immobilization reduced the number of crossed squares. Against the background of EMS, the number of crossed squares decreased again compared to gonadectomized unstressed and immobilized rats. Against the background of EMS, immobilized female rats showed a longer grooming duration compared to males. It was suggested that the adaptive mechanisms are more pronounced in intact female rats than in males. The effect of EMS on stress-induced motivational-emotional parameters of behavior depends on peripheral sex hormones.