Progenitor Stem Cells Behavior in the Adrenal Gland of Acute-Stress Albino Rat Model: A Histological and Immunohistochemical Study

Abstract

Background: The adrenal gland achieves a greater degree of plasticity in response to stress. This is attained through the proliferation and differentiation of the adult adrenal progenitors. Aim of the work: This work aimed to assess the presence of adrenal progenitor cells and their behavior under acute stress and recovery. Material and methods: Eighteen male rats (8 weeks, 200-250g) were equally divided into three groups: Control rats, Acute-Stress rats were exposed to restraint stress for 2 h without food and water during the stress period, recovered rats were exposed to the same pattern of stress, then housed in enriched environment supplied with running wheel for six days. After scarification, the blood samples were collected for plasma cortisol assessment, the glands were excised and processed for histological and immunohistochemical studies. Result: The cortisol level was elevated in the acute-stress group, but returned to normal level in the recovered group. The adrenal glands of the acute-stress group showed vacuolations, congestion, and hemorrhage, however, the recovered group showed improvement in the gland histology. Both Nestin and GFAP expressions were detected mainly in the capsular and subcapsular regions and medulla of all groups. The expression chromogranin-A was markedly increased in both acute-stress and recovered groups as compared to the control group, and it was greatly higher in the acute-stress group as compared to the recovered group indicated increased chromaffin cell number. Conclusion: In acute stress, Nestin progenitor cells of the adrenal gland were capable of differentiation into chromogranin-A expressing chromaffin cells