The effect of three Tujia herbs on the gut microbiota of mice with ulcerative colitis
Ulcerative colitis (UC) is a chronic non-specific inflammatory disease, characterized clinically by abdominal pain, diarrhea, mucus, pus, bloody stools, and other symptoms. The traditional Chinese medicine syndrome types of ulcerative colitis mainly include damp heat in the large intestine, liver depression and spleen deficiency, yin deficiency and intestinal dryness, spleen and stomach weakness, spleen and kidney yang deficiency, blood stasis and intestinal collaterals, and mixed cold and heat. Many medical practitioners follow the treatment principle of “legislation based on syndrome and prescription according to law”, and often use products that clear heat, promote dampness, nourish qi, and invigorate the spleen for treatment. The three needles (Berberidis Radix) are the dried roots of several species of plants belonging to the Berberidaceae family, such as the oyster pig thorn Berberis julianae Schneid, the small coptis thorn Berberis wilsonae Hemsl, the fine leaf Berberis poiretii Schneid, or the spoon leaf Berberis vernae Schneid. They are cold in nature, bitter in taste, and belong to the liver, stomach, and large intestine meridians. They have the effects of reducing fire, drying dampness, clearing heat, and detoxifying. They are authentic medicinal materials in Enshi Tujia and Miao Autonomous Prefecture. Tujia medicine often uses three needles alone or in combination with Yingshan Honggen, Pomegranate Peel, Wu Zhuyu, etc. to treat diarrhea and dysentery, with significant therapeutic effects, but its specific mechanism of action is not yet clear.
The gut microbiota is abundant and diverse, playing an important role in the host’s immune response, metabolism, and disease progression. The gut microbiota participates in the functions of intestinal mucosal barrier, substance absorption, metabolism, and nutrition, while mediating the proliferation and differentiation of T lymphocytes and regulating intestinal immune response. Numerous studies have shown that dysbiosis of the gut microbiota is closely related to ulcerative colitis, irritable bowel syndrome, and colorectal cancer. At present, aminosalicylic acid drugs, steroid drugs, immunosuppressants, or surgery are commonly used to treat ulcerative colitis, with average efficacy and easy recurrence. In recent years, relevant literature has reported that traditional Chinese medicine can effectively treat ulcerative colitis by regulating the structure of intestinal microbiota and restoring microbiota diversity. Based on this, we plan to investigate the effects of three drugs on the gut microbiota of mice with ulcerative colitis, in order to preliminarily explore their mechanisms of action from the perspective of gut microbiota mediation.

 

This experiment first validated the intervention effects of three drugs on UC mice in terms of weight changes, DAI scores, colon length, and tissue morphology. Secondly, the effects of three drugs on the gut microbiota of UC mice were examined. The results showed that the three needles significantly improved the weight, DAI score, and colon length of mice, reduced inflammatory infiltration, and repaired intestinal mucosal damage. The sequencing results showed that the three needles were able to significantly restore the disrupted microbiota structure induced by DSS, suggesting that the intervention effect of the three needles on UC may be highly correlated with the gut microbiota. In the Pcoa and cluster analysis of the gut microbiota in the normal group, model group, and three needle group, it was found that there were significant differences in the gut microbiota structure between the model group and the normal group mice. However, after intervention with three needles, the gut microbiota was significantly altered and approached the normal group, which was confirmed by community structure analysis and LEfSe analysis. Through gene function prediction, it was found that the intervention of three needles in UC may also be related to the metabolic function of gut microbiota, providing a new direction for subsequent research.
The gut microbiota, as a biological barrier in the intestinal mucosal barrier, is crucial for maintaining the balance between health and disease in the body and is part of the brain gut axis. The imbalance of gut microbiota can lead to the proliferation of harmful bacteria and the reduction of beneficial bacteria, resulting in structural disorder and decreased diversity of gut microbiota, thereby causing damage to the intestinal mucosa. Some studies suggest that the abnormal immune inflammatory response mediated by gut microbiota imbalance is one of the important causes of UC. Therefore, restoring the homeostasis of gut microbiota through microbial preparations has gradually become a new hotspot for treating UC. The main route of traditional Chinese medicine administration is oral decoctions, which inevitably come into contact with the gut microbiota in the body, producing a bidirectional regulatory effect. Some traditional Chinese medicines achieve therapeutic effects by restoring the structure and diversity of the gut microbiota and maintaining its homeostasis. Modern pharmacological studies have shown that the three needles mainly contain various alkaloids such as berberine, palmatine, jatrorrhizine, and palmatine. Research has shown that berberine can upregulate the abundance of Bacteroidetes and downregulate the abundance of Firmicutes. It can activate aryl hydrocarbon receptors (AhR) through gut microbiota related tryptophan metabolites to treat DSS induced ulcerative colitis in rats. Zhang et al. demonstrated through high-throughput sequencing results that palmatine upregulated the relative abundance of Bacteroidetes, increased beneficial bacteria, reduced harmful bacteria, and improved DSS induced ulcerative colitis by restoring bacterial diversity and inhibiting tryptophan degradation. The above research reports are basically consistent with the results of this experiment. At the same time, in the LEfSe analysis of this experiment, compared with the model group, Lactobacillus order, Lactobacillus genus, and Lactobacillus family were the dominant bacterial species shared by the normal group and the three needle group. Lactobacillus has been proven to improve diarrhea. In addition, Lactobacillus can improve the colonic mucosal barrier function of mice by inhibiting cytokine induced apoptosis in human colonic epithelial cells and increasing the content of mucin-2 (MUC-2). Clostridium is an obligate anaerobic bacterium that secretes exotoxins, posing a threat to human health. The increase in Clostridium promotes the occurrence of intestinal diseases. The three needle plant Coptis chinensis can inhibit the growth of clostridia and prevent intestinal cancer by reducing the number of clostridia. In this experiment, Clostridia genus, Clostridia class, and Clostridia order were the dominant bacterial species in the model group, while the normal group and the three needle group had lower abundance, which is relatively consistent with the results of literature research.