(A) Example of regional analysis scheme. For samples in the 'moderate' group, glycosaminoglycan concentration ([GAG]) maps measured after 3 weeks of recovery were segmented into 'low', 'medium', and 'high' regions, as specified in the Methods section under Image processing (so that the set of pixels defined as 'low' represented the regions of tissue that recovered the least during the 3-week recovery period and the set defined as 'high' represented tissue that recovered the most). The mean [GAG] of these three regions were followed in time. At each time point, segmented images were analyzed separately to assess whether GAG contents and recovery rates were comparable. (B) Weekly mean [GAG] ± SD of regions defined as 'low' (red), 'medium' (yellow), or 'high' (green), according to the process illustrated in panel A. (C) Weekly changes in mean [GAG] ± SD are shown for each region. Rate of [GAG] recovery is independent of absolute [GAG] for the first 2 weeks of culture after IL-1 exposure. 'Low', 'medium', and 'high' GAG regions recover at statistically different rates during the third week following IL-1 exposure (* P < 0.0001). All mean [GAG] values and recovery rates are derived from a total of 10 samples.