ABSTRACT
ObjectiveTo investigate the mechanism of Gegen Qinliantang（GQT） on the intestinal flora of antibiotic-associated diarrhea（AAD） by 16S rRNA sequencing and network pharmacology. MethodSixty SD rats were randomly divided into six groups（n=10）， including blank group， model group， GQT high-， medium- and low-dose groups（10.08， 5.04， 2.52 g·kg-1） as well as Lizhu Changle group（0.15 g·kg-1）， except for the blank group， each group was given clindamycin（250 mg·kg-1） by gavage once a day for 7 consecutive days. After successful modeling， the blank group and the model group were given equal volumes of normal saline by gavage. The other groups were given corresponding doses of drugs by gavage for 14 days. Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform（TCMSP） was used to screen the active components and targets of GQT， GeneCards， Online Mendelian Inheritance in Man（OMIM） database， Pharmacogenetics and Pharmacogenomics Knowledge Base（PharmGKB）， DrugBank and DisGeNET were used to search for AAD disease targets. The drug-disease common targets were obtained by R software. STRING was applied to analyze the target protein-protein interaction， and Kyoto Encyclopedia of Genes and Genomes（KEGG） pathway enrichment analysis was performed. Then hematoxylin-eosin（HE） staining was used to observe the pathological changes of the colon， and 16S rRNA sequencing of AAD colon content flora structure further verified the results of network pharmacology. ResultThrough network pharmacology， it was found that 238 active components were screened from GQT and acted on 276 component targets， among which quercetin， puerarin， wogonin and apigenin were the main core components of GQT， 1 097 AAD disease targets and 127 drug-disease intersection targets. The protein-protein interaction network mainly included core targets such as protein kinase B1（Akt1）， interleukin（IL）-6 and IL-1β， which were mainly enriched in the IL-17 signaling pathway. It was verified through animal experiments that compared with the blank group， the colon structure of the model group was seriously abnormal， the intestinal epithelial columnar cells were damaged， the goblet cells were reduced， and a large number of inflammatory cells were infiltrated. Compared with the model group， the colon structure of the GQT high-dose group improved， but there were still abnormalities， the colon structure of GQT medium- and low- dose groups and Lizhu Changle group improved significantly and reached the normal level. GQT could improve the structural diversity of AAD intestinal flora. At the phylum level， the abundance of Firmicutes was increased and the abundance of Bacteroidetes was decreased. At the genus level， the abundance of Lactobacillus was increased， and the abundances of Prevotella and Bacteroides were decreased. Among them， Lactococcus could be used as a biomarker for AAD treatment with GQT， and the prediction of functional metabolism of intestinal flora revealed that GQT could promote acetate and lactate metabolic pathways in the intestine. ConclusionGQT may activate IL-17 signaling pathway by acting on the targets of Akt1 and IL-6 through key components such as quercetin and wogonin， and improve the abundance of Lactococcus in the intestinal tract as well as acetate and lactate metabolic pathways， so as to play a role in repairing the intestinal barrier for the treatment of AAD.