Fig. 2: Metabolomics overview of metabolite concentrations in healthy ears and in inflamed ears with acute and chronic cutaneous DTHR.

a Principal component analysis (PCA) of the first two principal components (PC 1 (42.8%), PC 2 (36.6%)) scores plot illustrating the group separation based on the metabolite concentrations. Naive—dark grey squares, acute 4 h—medium grey upward triangles, acute 24 h—downward light grey triangles, chronic 0 h—yellow empty circles, chronic 4 h—beige dots with cross, chronic 12 h—orange full dots, chronic 24 h—brown exes. b PCA loadings plot illustrating the most significant metabolites that drive the principal component separation. c Averaged group heatmap illustrating normalised and autoscaled (-2; 2) metabolite concentration changes during acute and chronic cutaneous DTHR, red—relatively high concentration, blue—relatively low concentration. Metabolite list organised by Ward hierarchical clustering using Euclidean distance measure (n = 5 animals, except acute 24 h n = 4 animals). GDP guanosine diphosphate, IMP inosine monophosphate, GPC sn-glycero-3-phosphocholine, GSSG glutathione disulfide, UMP uracil monophosphate, ATP adenosine triphosphate.