Effects of cold water swim stress on volumetric parameters of adrenal gland in rats

Background: The adrenal gland is an essential organ in systems that are responsible for the maintenance of homeostasis during stress. The aim of this study was to examine the effects of cold water swim stress (CWSS) on the volumetric parameters of rat adrenal gland.
Materials and Method: In this experimental study, 20 mature male Sprague Dawley rats, weighing 200±30 g were selected and randomly divided into two  equal study and control groups (n=10). Stress was induced by forced swimming in cold water (15°C), 2 min daily for 20 days. The animals were weighed and decapitated. Their adrenal glands were excised quickly, freed of fat tissue, weighed, and fixed in Lilli’s solution and embedded in paraplast, according to routine histological procedures. Five µm sections were cut using microtome and stained by the Masson trichrome technique. Volumetric parameters of adrenal gland and its components were estimated using point counting method. The Mann Whitney-U test was employed to determine statistically significant differences between the means.
Results: Results showed that cold water swim stress induced a significant reduction in body weight (p<0.01), and a significant increase in relative adrenal weight (p<0.001). The absolute volume of zona fasciculata increased significantly (p<0.05) and the volume fraction of zona reticularis decreased significantly (p<0.05) in CWSS compared to the control group.
Conclusion: Cold water swim stress (CWSS) produces volumetric changes in the rat adrenal glands. Different zones of the glands respond differently to cope with this stress