Figure 2.
A: stress-strain curves of an airway ring exposed to 10−5 M cytochalasin D for 1 h before (dashed dark gray line) and after (dark gray line) treatment with riboflavin and UV-A. The Young’s modulus, E, was calculated as the slope of the stress-strain curve at 60% radial strain. Exposure to cytochalasin D reduces the contribution of the cells to the total tissue stiffness to negligible levels, therefore, the value of E measured here represents extracellular matrix (ECM) stiffness. B: following collagen crosslinking, E increased for all airway ring samples tested (dark gray circles, n = 9). The effect was statistically significant (P < 0.001, paired t test, n = 9). The percentage increase in E is shown in the inset figure. n, number of airway rings tested; *statistical significance (P < 0.05).