Statistical analysis
Data are presented as the mean ± standard deviation or mean ± stanard error of the mean from at least three independent experiments. The unpaired Student’s t - test for comparing two groups or one-way analysis of variance for comparing multiple groups was used to analyze statistical significance using GraphPad Prism 8 (GraphPad Software, San Diego, CA, USA). Hierarchical cluster analysis of different metabolites was performed by Python. The raw metabolomic intensity of each metabolite from two groups was transformed into the Log2 value of normalized intensity. For all statistical analyses, a significant difference was accepted at P< 0.05.