Association of T cell infiltration and morphological change of thymus gland with the aggravation of pulmonary emphysema in testosterone deficiency

Chronic obstructive pulmonary disease is an inflammatory lung disease characterized by chronic bronchitis and emphysema. Our previous study revealed that testosterone depletion induced T cell infiltration in the lungs and aggravated pulmonary emphysema in orchiectomized (ORX) mice exposed to porcine pancreatic elastase (PPE). However, the association between T cell infiltration and emphysema remains unclear. The aim of this study was to determine whether thymus and T cells are involved in the exacerbation of PPE-induced emphysema in ORX mice. The weight of thymus gland in ORX mice was significantly greater than that of sham mice. The pretreatment of anti-CD3 antibody suppressed PPE-induced thymic enlargement and T cell infiltration in the lungs in ORX mice, resulting in improved expansion of the alveolar diameter, a marker of emphysema exacerbation. These results suggest that increased thymic function due to testosterone deficiency and the associated increased pulmonary infiltration of T cells may trigger the development of emphysema.