Abstract: This study was conducted to investigate the effects of Radix Salviae Miltiorrhizae on the intestinal flora of mice injected with Escherichia coli(E. coli) based on network pharmacology and 16S rDNA high-throughput sequencing technology. The active components and corresponding targets of Radix Salviae Miltiorrhizae were screened by Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, and the E. coli targets were searched by Genecards database. Protein interaction analysis of the intersection of the target genes was performed through SRTING database to construct the protein-protein interaction(PPI) network, and the "Radix Salviae Miltiorrhizae active ingredient-potential action target" network was constructed by Cytoscape 3.8.2 software. DAVID online tools were used to analyze the function of gene ontology (GO), Metascape online tools were used to analyze the enrichment of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. One hundred and ten male Kunming mice were randomly divided into control group, E. coli group, and low-, medium- and high-dose Radix Salviae Miltiorrhizae injected with E. coli group, with 22 mice in each group. E.coli O₁₀₁ was injected intraperitoneally after continuously gavaged with Radix Salviae Miltiorrhizae solution for 28 days, while sterile normal saline was injected into the control group. After observation for 24 h, feces were collected from each group. The 16S rDNA high-throughput sequencing technology was used to analyze the intestinal flora of mice in each group. The results were showed as follows:1) The network pharmacological analysis showed that the active components of Radix Salviae Miltiorrhizae were 36, and the number of action targets was 669. The Genecards database searched for 8 902 E. coli targets, and the intersection between the two was selected and isolated points were removed, finally, 51 potential targets for E. coli treatment with Radix Salviae Miltiorrhizae were obtained. Through GO and KEGG analysis, 18 key targets and 16 key pathways were identified, including 174, 76 and 45 biological processes (BP), molecular functions (MF) and cellular components (CC), respectively; 2) A total of 950 855 valid sequences and 2 537 operational classification units (OTUs) were obtained by Illumina Miseq sequencing; 3) Alpha diversity analysis results showed that the intestinal flora diversity of Radix Salviae Miltiorrhizae groups was significantly different from that of the control group, and the intestinal flora diversity of the E. coli group was significantly lower than that of the control group (P<0.05); 4) Compared with E. coli infection group, at the phylum level, the abundance of Bacteroides was extremely significant increased(P<0.01) and Firmicutes was significantly increased(P<0.05) and Proteobacteria was extremely significant decreased (P<0.01) in the low-, medium- and high-dose Radix Salviae Miltiorrhizae injected with E. coli groups, while at genus level, the abundance of Bacteroides was extremely significant increased (P<0.01); 5) Based on LEfSe analysis, a total of 14 significantly different microflora were found in the control group, E. coli infection group, and high-dose Radix Salviae Miltiorrhizae injected with E. coli group. 6) PICRUSt functional prediction analysis showed that the main functional pathways of Radix Salviae Miltiorrhizae for intestinal flora of mice infected with E. coli were amino acids, carbohydrate transport and metabolism; Translation, ribosomal structure and biotransformation; Cell wall/membrane/biosynthesis, etc. In summary, network pharmacology combines with 16S rDNA high-throughput sequencing technology has revealed that Radix Salviae Miltiorrhizae regulates the relative microflora biological abundance through multi-component, multi-target, and multi-pathway, which alleviates the intestinal flora damage in mice with flora imbalance caused by E. coli infection, and provides theoretical basis for clinical application of Radix Salviae Miltiorrhizae in the treatment of E. coli infection.

Key words: Radix Salviae Miltiorrhizae, network pharmacology, intestinal flora, high-throughput sequencing, mice