The effect of a voluntary physical activity on corticosterone and anxiety levels during and after pregnancy in mice

Evidence shows that certain conditions during pregnancy will have lasting effects on the fetus. The aim of this study was to investigate the effect of a period of voluntary physical activity on corticosterone and anxiety levels in mice during and after pregnancy.  

In this experimental study, 40 female NMRI mice aged with an approximate age of 80 to 90 days and a weight of 25 to 30 grams were divided into four groups of 10 including the control-pregnancy, experimental-pregnancy, control-postpartum and experimental-postpartum groups. After two weeks of adaptation to the environment and seeing the vaginal plaque, two rotating wheels were placed inside the cage of each pregnant mice to apply voluntary physical activity for four weeks. The dark-light box test was used to measure the anxiety of mice. Finally, the animals of the pregnancy groups, on the 18th day of pregnancy and the samples of the postpartum groups, on the 7th day after delivery; were given deep anesthesia and to measure corticosterone, blood was taken directly from the heart tissue. For statistical analysis, the independent sample t-test was used at a significance level of p<0.05.

The serum corticosterone levels decreased significantly in the experimental groups during pregnancy (p=0.002) and during the postpartum periods (p=0.006). However, the anxiety level of the mice was significantly reduced only in the experimental postpartum group (p=0.007).

The use of voluntary physical activities during pregnancy in mice is probably important as an effective therapeutic strategy in reducing cortisol and psychological disorders including anxiety.