Fig. 8

Comparison of rabbit scleral resistance to MMP1 after cross-linking with glutaraldehyde (GA, 1%, 5 min), paraformaldehyde (PFA, 4%, 5 min), riboflavin/UV-A-light (0.5% riboflavin; 40 and 75 mW/cm², 20 min irradiation time) and riboflavin/blue light (0.5% riboflavin; 40 and 150 mW/cm², 20 min irradiation time) of different light intensities. The amount of peptide in the supernatant was calculated as percentage of the degradation products of the untreated (non-cross-linked) control value after 24 h (each 24 h value of the corresponding internal control patch was set 100%). Each of the cross-linking methods reduced the degradation of rabbit sclera by MMP1. Cross-linking with the chemical cross-linkers GA and PFA reduced the degradation to 7% at 24 h (n = 5). The treatment with riboflavin/UV-A-light reduced the enzymatic degradation of rabbit sclera to 62% at 24 h (n = 4). No significant differences in resistance to enzymatic degradation were detected using higher light intensities. After riboflavin/blue light cross-linking the enzymatic degradation of rabbit sclera was reduced to 77% at 24 h (n = 6). No differences in resistance to enzymatic degradation were detected using higher light intensities. Means and standard deviation are presented. The statistical analysis was performed with the Mann-Whitney U-Test to the corresponding control (unpaired, two tailed), p* < 0.05, p** < 0.01