Exposure to forced swim stress alters morphofunctional characteristics of the rat thymus

Abstract The aim of this study was to investigate whether chronic stress, induced by repeated daily swimming during 21 days, alters the morphofunctional parameters in the thymus of adult rats. Our results showed that chronic stress reduced thymus mass, total number of thymocytes, volume of the thymus compartments and numerical density of thymocytes within thymus inner cortex and medulla. However, the percentage of apoptotic cells and the level of corticosterone were significantly increased. The percentages of CD4-CD8-TCRαβ low/high and CD4-CD8+TCRαβ - thymocytes were significantly increased, while the percentage of the least mature CD4+CD8-SP TCRαβ − thymocytes was significantly decreased. These results show that recurred swimming procedure induces thymus hypotrophy and elevated percentage of DN TCRαβ + cells.