Summary of differentially expressed proteins (DEPs) detected in two iTraq experiments and Gene Ontology enrichment analyses of DEPs. (A) Overview of DEPs in two iTraq experiments. (B) An x-y scatter plot used to analyze the consistency of two sets of iTraq data, whereby the x-axis represents the log value of the protein level in the UC-MSC-to-BM-MSC (UC/BM) ratio in the first mass spectrometry detection, and the y-axis represents that parameter in the second detection. Histograms showing DEP enrichment in biological processes (C), cellular components (D), and molecular functions (E). The enrichment degree was described by the ratio of the number of targeted proteins to all the annotated proteins. BM-MSC, bone marrow mesenchymal stem cell; iTraq, isobaric tagging for relative and absolute quantitation; UC-MSC, umbilical cord mesenchymal stem cell.