Early changes in lung tissue following ionizing radiation (IR) initiate processes that may lead to either regeneration or fibrosis. Intercellular junction proteins play a crucial role in the organization and function of epithelial tissues, both under normal conditions and after injuries. Alterations in the expression and localization of these proteins can influence the fate of epithelial cells. This study aims to investigate the effects of IR on lung tissue structure, as well as on the levels and distribution of intercellular junction proteins. Wistar rats were subjected to total X-ray irradiation at doses of 2 and 10 Gy. Lung tissue samples were collected for Western blot and histological analysis 72 h post-IR. IR at doses of 2 and 10 Gy led to structural changes in lung tissue and elevated levels of E-cadherin. The 10 Gy IR resulted in increased claudin-4 and occludin in lung parenchyma, decreased claudin-8 and claudin-12 in bronchial epithelium and endothelium, and suppression of apoptosis. Data evaluation indicated that alterations in the protein composition of intercellular junctions are essential processes in lung tissue at early stages after IR, and at least some of these alterations are associated with adaptation.