The Behavioral Effects of Prenatal Stress on Adolescent Offspring of Rats under Pregnancy Stress

Stress is a strong stimulant that is considered as a damaging factor for a number of psychiatric and neurobiological disorders. Among different periods of life, embryonic life has a high degree of sensitivity and flexibility; hence, maternal experiences during pregnancy can form and predict the behavior of her descendent. In the present study, a new model of social stress was used during the rat pregnancy period to examine its influence over the behavior of adolescent offspring. Twenty Wistar rats (weighed approximately150-200gr) were used. After gestation, rats were divided into a control group and a stress group. The stress group members were subjected to restraint stress and predator stress with social instability since the second week of pregnancy. The effect of maternal stress was studied in offspring by dark-light box test during adolescence. The stress group showed a significant increase in the delay time for the first entry into the light box (T1) in comparison to the control group (p =0.0020(. The total time the animal remains in the light box (T2) and the number of the entries into the light box (n) decreased in comparison with control group, respectively )p =0.0003, p <0.0001). These variations were more prominent for males than females for all the above mentioned parameters. The induction of a new social stress model had a significant and different impact on the behavior of the mother and her offspring in adulthood. The results also revealed the difference between male and female resistance to stress.