Older rat lungs had a more stable support network

Older lungs accumulated mature collagen crosslinks, bonds that reinforce a structural protein in the extracellular matrix—the support network outside cells. Their matrix architecture was more stabilized, indicating reduced ability to change structure. Young lungs showed coordinated matrix assembly and protein patterns consistent with structural adaptability and mechanical resilience. Older lungs also showed protein patterns suggesting metabolic stress and immune activation. Aging effects varied across lung regions and were more pronounced in females. The authors identified matrix stabilization as a central feature of lung aging.