Fig. 2.

Proteomic overview of the three biological replicates. (A) A Venn diagram reveals a large overlap of MS-identified proteins between biological replicates. 500 proteins were found in medium samples from all three animals, and few proteins were found in only one or two animals. (B) Principle component analysis (PCA) was performed using abundance values for 456 filtered proteins obtained from MS analysis of cartilage explant medium samples taken on day 4, 8, 12, 16, and 20 of culture from the treatment groups control (N), injury (I), cytokines (C), and injury + cytokines (IC). The data clearly separate into two clusters, one with treatments N and I, and the second with treatments C and IC. Percentages on axes represent percent variance explained by that principal component. The large symbol within each cluster represents the cluster centroid.