Glycosaminoglycan (GAG) release from cartilage blocks determined after treatment with surface-degrading agents. Cartilage blocks were subjected to pre-treatment with trypsin, pepsin, or guanidine, as indicated for the bonding experiments; the samples in the control group were incubated in PBS buffer. (a) Subsequently, the GAG content within the cartilage blocks was determined. (b) Additionally, the amount of GAG released into the medium (per cartilage block) was measured. Nine samples were measured per group. Bars represent the mean with standard error of the mean. P values are from post hoc Tukey test for pairwise comparisons. (c) Additionally, histological cross-sections of cartilage blocks were stained for GAGs.