Introduction Women are more vulnerable to stress‐related disorders than men, which is counterintuitive as female sex hormones, especially estrogen, have been shown to be protective against stress disorders. Methods In this study, we investigated whether two different models of stress act differently on ovariectomized (OVX) rats and the impact of estrogen on physical or psychological stress‐induced impairments in cognitive‐behaviors. Adult female Wistar rats at 21–22 weeks of age were utilized for this investigation. Sham and OVX rats were subjected to physical and psychological stress for 1 hr/day for 7 days, and cognitive performance was assessed using morris water maze (MWM) and passive avoidance (PA) tests. The open field and elevated plus maze tests (EPM) evaluated exploratory and anxiety‐like behaviors. Results In sham and OVX rats, both physical and psychological stressors were associated with an increase in EPM‐determined anxiety‐like behavior. OVX rats exhibited decreased explorative behavior in comparison with nonstressed sham rats (p < .05). Both physical stress and psychological stress resulted in disrupted spatial cognition as assayed in the MWM (p < .05) and impaired learning and memory as determined by the PA test when the OVX and sham groups were compared with the nonstressed sham group. Estrogen increased explorative behavior, learning and memory (p < .05), and decreased anxiety‐like behavior compared with vehicle in OVX rats exposed to either type of stressor. Conclusions When taken together, estrogen and both stressors had opposite effects on memory, anxiety, and PA performance in a rat model of menopause, which has important implications for potential protective effects of estrogen in postmenopausal women exposed to chronic stress.

Environmental enrichment (EE) has shown remarkable effects in improving cognition and addictive behaviour. We tested whether EE could help recover from prenatal stress exposure. Mature Swiss Webster male and virgin female mice were placed together until vaginal plugs were detectable. Next, pregnant rodents were randomized into the control, physically and psychologically stressed groups. The application of stress was initiated on the 10th day of pregnancy and persisted for a week to induce stress in the mice. Open field and elevated plus‐maze (EPM) tests were utilized as explorative and anxiety assays, respectively. A passive avoidance shuttle‐box test was carried out to check anxiety‐modulated behaviour. Morris water maze (MWM) test was undertaken to evaluate spatial learning and memory. Conditioned place preference (CPP) test was selected for evaluation of tendency to morphine consumption. Our results showed that prenatal stress elevated anxiety‐like behaviour in the offspring which EE could significantly alleviate after weaning. We also found a higher preference for morphine use in the physical stress and psychological stress offspring group. However, no difference was observed among the genders. Application of EE for the stress group improved several parameters of the cognitive behaviour significantly. Although prenatal stress can lead to detrimental behavioural and cognitive outcomes, it can in part be relieved by early exposure to EE. However, some outcomes linked to prenatal stress exposure may not be diminished by EE therapy. In light of such irreversible effects, large‐scale preventive actions promoting avoidance from stress during pregnancy should be advised.

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Background and aims: One of the main potential problems of radiotherapy (RT) in breast cancer is the increase in treatment-related inflammation. This study aimed to investigate the effect of eight weeks of moderate-intensity aerobic training (AT) on serum levels of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) in rats undergoing RT. Materials and Methods: In this experimental study, 32 male rats were randomly divided into four groups of eight members including (1) healthy control (C), (2) AT, (3) RT, and (4) AT + RT groups. Rats were first anesthetized with ketamine-xylazine solution (K, 60-90 kg/mg; Z, 6-10 kg/mg) and then located on a Plexiglas plate with a thickness of 1 cm. Photon beam RT was performed using X-rays with a dose of 11 Gy from an Elekta compact linear accelerator (Elekta Compact 6-MV China). AT program was performed for eight weeks, five days a week, and one session a day for 60 minutes (70-75% of VO2max). Afterwards, one-way ANOVA was run to examine the research variables. Results: According to the results, TNF-α was significantly higher in the RT group compared to the C group (P=0.003), whereas IL-6 levels were significantly lower in the AT + RT group compared to the RT group (P=0.001) and the C group (P=0.027). Further, the levels of this cytokine were significantly lower in the AT group compared to the RT group (P=0.006) and similarly in the RT group compared to the C group (P=0.03). Conclusion: RT led to an increase in pro-inflammatory cytokines; however, performing AT could only significantly reduce the IL-6 levels.

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