There is a bidirectional relationship between intestinal flora and bile acids,and the imbalance of intestinal flora-bile acid axis metabolism is closely related to hypertension.Based on classical TCM literature and clinical practice,this article found that"earth deficiency"is the important pathological basis of hypertension,"wood depression"is the initiating factor of hypertension,and"earth deficiency and wood depression"is the key pathogenesis of hypertension.Combined with the research results of modern medicine and molecular biology,it is considered that the imbalance of intestinal flora and abnormal bile acid metabolism are closely related to the"earth deficiency"and"wood depression"of TCM respectively,and the imbalance of intestinal flora-bile acid axis coincides with the"earth deficiency and wood depression"of TCM in the process of hypertension.It is of great theoretical and practical significance to explore the biological connotation of hypertension"earth deficiency and wood depression"from the perspective of intestinal flora-bile acid axis for guiding TCM to prevent and treat hypertension.

ObjectiveTo observe the effect of Zhengan Xifengtang on blood pressure and fecal microflora of spontaneously hypertensive rats （SHRs）. MethodA total of 75 male SHRs aged nine weeks were randomly divided into SHR group， Benazepril group （1.00 mg·kg^-1·d^-1）， high-dose Zhengan Xifengtang group （34.5 g·kg^-1·d^-1）， medium-dose Zhengan Xifengtang group （17.25 g·kg^-1·d^-1）， and low-dose Zhengan Xifengtang group （8.625 g·kg^-1·d^-1）. A total of 15 male Wistar-Kyoto （WKY） rats aged nine weeks were selected as the normal group. The normal group and SHR group were administrated with an equal volume of distilled water for eight weeks. During the administration， the blood pressure of the rats was measured regularly. After the intervention， fresh feces were collected with a sterile frozen storage tube， and 16S amplicon information was collected and analyzed. Plasma， hippocampus， and ileum of rats were collected for ultra-high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） detection. ResultZhengan Xifengtang decreased the systolic blood pressure and diastolic blood pressure of SHRs. Compared with the SHR group， Zhengan Xifengtang decreased the diversity of fecal microflora of SHRs. At the phylum level， Zhengan Xifengtang increased the relative abundance of SHR Verrucomicrobia and Actinobacteria and decreased the relative abundance of Synergistetes， Tenericutes， and Candidatus Saccharibacteria. Compared with the SHR group， Zhengan Xifengtang increased the relative abundance of Blautia wexlerae， Fusicatenibacter saccharivorans， and Akkermansia muciniphila and decreased the relative abundance of Clostridium lavalense， Intestinimonas butyriciproducens， Acetatifactor muris， Alloprevotella rava， and Oscillibacter valericigenes. Spearman correlation analysis showed that the systolic blood pressure of rats was negatively correlated with the relative abundance of Ethanoligenens， Aerococcus， Butyrivibrio， Olsenella， Bifidobacterium， Clostridium XIVb， Allobaculum， and Fusicatenibacter and positively correlated with the relative abundance of Alloprevotella. Zhengan Xifengtang increased the contents of plasma， hippocampal 5-hydroxy tryptamine（5-HT）， and 5-hydroxyindole acetic acid（5-HIAA） in SHRs and decreased the contents of 5-HT and 5-HIAA in the ileum， and the content of 5-HT in the hippocampus was negatively correlated with that in the ileum. ConclusionZhengan Xifengtang can reduce the blood pressure of SHRs， which may be related to reducing the diversity of SHR microflora， regulating the structure of the microflora， increasing the relative abundance of 5-HT and short-chain fatty acids bacteria， and lowering the relative abundance of pathogenic bacteria related to intestinal inflammation.

Metabolic regulation has been proven to play a critical role in T cell antitumor immunity. However, cholesterol metabolism as a key component of this regulation remains largely unexplored. Herein, we found that the low-density lipoprotein receptor (LDLR), which has been previously identified as a transporter for cholesterol, plays a pivotal role in regulating CD8