The Influence of Exposure to Stress of Pregnant Rats on the Adrenal Gland Structure of their Offspring. An Unbiased Stereological Study

Abstract

Many factors may interact with normal differentiation and growth of tissues and cells. Stress might be  experienced during pregnancy and it has been shown that stress may cause low birth weight. The effect of  prenatal manipulations on the HPA axis has been focused on physiological and biochemical alteration of  the adrenal gland. A stereological examination of the influences of prenatal stress on the structure of the  developing adrenal gland of one day and 21 day-old rats has now been performed. 

In this study experiments were conducted to test the hypothesis that exposure to restraint stress during pregnancy  in rat results in structural changes in the developing adrenal gland of their pups. 

Female rats were exposed to restraint stress from the first day of pregnancy throughout gestation. Male offspring  of stressed rats (PS= experimental) and of unstressed mothers (C= control) who were one day and 21  days of age were selected. Their body weight (BW), crown-rump length (CRL), biparietal diameter (BPD),  volume of the gland and the cortical layers and medulla were estimated using stereological methods. 

The results showed that the prenatal stress led to a decrease in BW, but CRL and BPD remained unchanged.  Also, a significant increase in volume of the adrenal gland and cortical layers in one day and 21 day-old  offspring were observed. The volume of the medulla of the adrenal gland of neonate rats remained  unchanged but the volume of the medulla in 21 day-old rats was decreased. 

Therefore, it can be concluded that prenatal stress alters the structure of the developing adrenal gland.