Cadmium-induced lung injury disrupts immune cell homeostasis in the secondary lymphoid organs in mice

Cadmium (Cd) is a well-known toxic heavy metal that poses significant health risks, particularly through inhalation, smoking, and the consumption of contaminated food. Exposure to cadmium is linked to the development and exacerbation of chronic lung diseases such as pulmonary fibrosis and chronic obstructive pulmonary disease (COPD). This study investigated the systemic effects of intratracheal cadmium chloride (0.5 mg/kg) instillation in C57BL/6 mice. All parameters, including inflammation assessment, lung function evaluation (using Flexi-vent), and immunophenotyping of T-cells in secondary lymphoid organs (mediastinal lymph nodes and spleen), were analyzed 14 days after cadmium exposure. The results demonstrated that cadmium exposure led to significant immune cell infiltration in bronchoalveolar lavage (BAL) fluid, altered pro-inflammatory cytokine levels, and was associated with impaired lung function, characterized by increased lung resistance and Newtonian resistance. Analysis of T-cell populations revealed no significant changes in total T-cells in mediastinal lymph nodes and spleen, but a decrease in CD4⁺ T-cells and an increase in CD8⁺ T-cells were observed. These findings suggest that cadmium disrupts T-cell homeostasis in secondary lymphoid organs. Further research is crucial to elucidate the mechanisms underlying cadmium-induced lung injury and immune dysregulation, essential for developing effective therapeutic interventions against chronic lung diseases caused by cadmium exposure.