The thymus structural organization in severe extracellular dehydration and during readaptation

Aim: To investigate the changes of the thymus structure under extracellular dehydration and after rehydration in model experiment.

Materials and Methods: The study was conducted on 40 white male rats, divided into 4 groups of 10 animals each. 2 experimental groups were subjected to extracellular dehydration during 90 days. Following this period, one group was removed from the experiment and other one was switched to the vivarium's standard ration for 30 days (rehydration). The control groups of animals received the vivarium's standard ration throughout the 90 days and the 120 days respectively. The morphometric analysis, histological examination, immunohistochemical analysis were used.

Results: 90 days extracellular dehydration leads to deformation of the thymocytes nuclei of rats, vacuolation or organelle destruction in cytoplasm, apoptosis and necrosis activation. The signs of stasis and thrombosis are present in thymic vessels. Functional thymus tissues replaced with connective and adipose tissues almost completely. After 30 days of rehydration reveals partial thymus restoration with lymphoid cell density increasing, with preserved morphological signs of cellular stress and structural remodelling, vascular abnormalities and incomplete restoration of thymus mass.

Conclusions: In the context of severe extracellular dehydration, profound the depletion of functional thymus tissue, its substitution with connective and adipose tissue, and the occlusion of blood vessels. The morphological structure of the thymus doesn't complete recover during 30 days readaptation period. This suggest the need for prolonged rehydration periods or more effective interventions to fully restore thymic structure and function.