Fig. 3
Effect of TiO2 NPs on liver metabolism analyzed by non-targeted metabonomics using HPLC-MS. a Heatmap of metabolite concentrations, which shows the different metabolites in liver tissues of rats in the control group and high-dose TiO2 NPs (50 mg/kg) treated group. Each row represents a metabolite, and each column represents a sample. The color of each grid represents the relative concentration of the metabolites in the corresponding sample. b PCA and OPLS-DA scoring maps of metabolites in the control and TiO2 NPs treated group as well as quality control (Qc) samples. c Z Score Map of differential metabolites between the liver samples in the control and TiO2 NPs treated group. Z score = (the sample concentration - average concentration of samples in the control group)/ standard deviation of sample concentrations in the control group. Each point represents a sample, blue as the control group and red as the treat group. d KEGG pathway analysis of differential metabolites. X-axis represents the Pathway Impact obtained by the out-degree centrality algorithm. The size of the point is related to the Pathway Impact. Y-axis represents the negative logarithm of the p value (−log(p)) obtained by the pathway enrichment analysis. The yellow-red color change of the point is positively related to the -log(p). The names of pathways are labeled in the graph with -log(p) > 2 or Pathway Impact > 0.1