[Establishment and evaluation of a rat model of ulcerative colitis with syndrome of dampness stagnancy due to spleen deficiency]

Shenling Baizhu Decoction treats ulcerative colitis of spleen-deficiency and dampness obstruction types by targeting 'gut microbiota and galactose metabolism-bone marrow' axis

ETHNOPHARMACOLOGICAL RELEVANCE

Shenlin Baizhu Decoction (SLBZD), which comes from 'Taiping Huimin Heji Ju Fang', belongs to a classical prescription for treating spleen deficiency and dampness obstruction (SQDDS)-type ulcerative colitis (UC) in traditional Chinese medicine. However, the mechanism of SLBZD in treating UC with SQDDS remains unclear.

AIM OF THE STUDY

This study aims to investigate the mechanism of SLBZD against SQDDS-type UC of based on the "gut microbiota and metabolism - bone marrow" axis to induce endogenous bone marrow mesenchymal stem cells (BMSCs) homing.

MATERIALS AND METHODS

Ultra-performance liquid chromatography-mass spectrometry was used to analysis of SLBZD qualitatively. The efficacy of SLBZD in SQDDS-type UC was evaluated based on the following indicators: the body weight, colon length, disease activity index (DAI) score, Haemotoxylin and Eosin (H&E) pathological sections, and intestinal permeability proteins (occluding and ZO-1). 16S rRNA gene sequencing and non-target metabolomics were performed to identify gut microbiota changes and its metabolites in feces, respectively. BMSCs in each group was collected, cultured, and analyzed. Optimal passaged BMSCs were injected by tail vein into UC rats of SQDDS types. BMSCs homing to the colonic mucosal tissue was observed by immunofluorescent. Finally, the repairing effect of BMSCs homing to the colonic mucosal tissue after SLBZD treatment was analyzed by transmission electron microscopy, qRT-PCR, and immunohistochemistry.

RESULTS

SLBZD effectively improved the colonic length and the body weight, reduced DAI and H&E scores, and increased the expression of the intestinal permeability proteins, including occluding and ZO-1, to treat SQDDS-type UC. After SLBZD treatment, the α-diversity and β-diversity of the gut microbiota were improved. The differential microbiota was screened as Aeromonadaceae, Lactobacillaceae, and Clostridiaceae at the family level, and Aeromonas, Lactobacillus, Clostridium_sensu_stricto_1 at the genus level. Meanwhile, the main metabolic pathway was the galactose metabolism pathway. SLBZD treatment timely corrected the aberrant levels of β-galactose in peripheral blood and bone marrow, senescence-associate-β-galactosidase in BMSCs, and galactose kinase-2, galactose mutase, and galactosidase beta-1 in peripheral blood to further elevate the expression levels of senescence-associated (SA) proteins (p16, p53, p21, and p27) in BMSCs. The Spearman's correlation analysis demonstrated the relationship between microbiota and metabolism, and the relationship between the galactose metabolism pathway and SA proteins. After BMSCs in each group injection via the tail vein, the pharmacodynamic effects were consistent with those of SLBZD in SQDDS-type UC rats. Furthermore, BMSCs have been homing to colonic mucosal tissue. BMSCs from the SLBZD treatment group had stronger restorative effects on intestinal permeability function due to increasing protein and mRNA expressions of occludin and ZO-1, and decreasing the proteins and mRNA expressions of SDF-1 and CXCR4 in colon.

CONCLUSIONS

SLBZD alleviated the damaged structure of gut microbiota and regulated their metabolism, specifically the galactose metabolism, to treat UC of SDDOS types. SLBZD treatment promotes endogenous BMSCs homing to colonic mucosal tissue to repaire the intestinal permeability. The current exploration revealed an underlying mechanism wherein SLBZD activates endogenous BMSCs by targeting 'the gut microbiota and its metabolism-bone marrow' axis and repairs colonic mucosal damage to treat SDDOS-type UC.

Animal Models and Pathogenesis of Ulcerative Colitis

Background

Ulcerative colitis (UC) is a kind of inflammatory bowel disease which is needed to be predicted.

Objective

To analyze various animal models of UC conditions and summarizes the animal selection, model progression, and pathogenic mechanisms of UC animal models.

Methods

We surveyed the research papers published in PubMed, Google Scholar, Baidu Scholar, CNKI, SciFinder, and Web of Science in the past 5 years and discussed the experimental animals, modeling methods, and pathogenic mechanisms.

Results

In the selection of experimental animals, rats are considered the best experimental animals. The mainstream modeling methods can be categorized into the chemical stimulation method, immune stimulation method, and compound method, among which the compound method is the most successful. In the study of the pathogenesis of UC, the pathogenesis of UC is due to various pathogenic factors, such as nitric oxide (NO), prostaglandins (PG), proinflammatory factors (IL, TNF-α), and intestinal flora.

Conclusion

The method of building an animal model of UC is well-established, providing a more targeted selection of animal models for future related experiments.

Effect of Shenling Baizhu San on Intestinal Flora in a Rat Model of Ulcerative Colitis with Spleen Deficiency and Dampness

OBJECTIVE

Shenling Baizhu San (SLBZS) is reported as an effective drug for ulcerative colitis (UC); however, its effect on intestinal flora remains unknown. In this study, we investigated the effect of SLBZS on intestinal flora in a rat model of UC with spleen deficiency and dampness.

METHODS

UC was induced in rats using 2,4,6-trinitrobenzene sulfonic acid on the basis of a model of spleen deficiency and dampness. The 16S rDNA sequencing was used to detect structural changes in the intestinal flora; the phylogenetic investigation of communities by reconstruction of unobserved state (PICRUSt) analysis was used to predict the altered pathways.

RESULTS

Compared with the model group, rats in the SLBZS group exhibited decreased levels of TNF-α(P < 0.05), and increased abundance and diversity of the intestinal flora. The abundance of Actinobacteria (P < 0.001) and Bacteroides (P < 0.01) increased and that of Firmicutes decreased (P < 0.001), and the abundance of Bifidobacterium(P < 0.05) and Allobaculum increased. PICRUSt analysis showed that the altered pathways between the groups were those of fatty acid and antibiotic biosynthesis, amino acid metabolism, and the pentose phosphate pathway.

CONCLUSIONS

SLBZS can regulate the structure and function of the intestinal flora, alter expression levels of certain metabolic pathways, and has the potential to treat UC.

Therapeutic Effect of Ershen Pill () Extract on Pi (Spleen)-Shen (Kidney) Yang Deficiency-Induced Diarrhea in Rat Model

OBJECTIVE

To investigate whether Ershen Pill (ESP, ) could alleviate the symptom of Pi (Spleen)-Shen (Kidney) yang deficiency (PSYD)-induced diarrhea in rat model and explore its anti-diarrhea mechanism.

METHODS

Seventy-five Sprague-Dawley rats were divided into 5 groups by a random number table, including control, positive, model, low-dose (LD) and high-dose (HD) ESP groups, 15 rats in each group. All the rats, except those in the control group, were developed PSYD induced-diarrhea based on its pathology and etiology. The rats in positive, LD and HD ESP groups were treated with Shenling Baizhu Pill (), LD (1.05 g/kg) or HD (3.50 g/kg) ESP petroleum ether extract once a day for 2 weeks, respectively. Body weight change and diarrhea index were measured. The histology scores of the kidney were evaluated via hematoxylin and eosin (HE) staining. Aquaporin-3 (AQP3) expression in the colon was analyzed by immunofluorescence, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot, respectively.

RESULTS

Compared with the model group, oral administration of LD and HD ESP prevented body weight loss and inhibited diarrhea after 2-week treatment (P<0.05). Kidney deterioration was impeded, and the histology score in LD and HD ESP groups were 8.2 and 10.5, respectively, which were both higher than those in the model group (P<0.05). In addition, ESP treatment alleviated rat colitis, and HD ESP significantly improved the AQP3 positive staining intensity in the colon tissue compared with the model group. The result from Western blot revealed that AQP3 protein synthesis in colon tissue of LD and HD ESP groups increased by 2.1- and 5.9-fold compared with the model group (P<0.05). qRT-PCR result showed that AQP3 gene expression in the HD ESP group was also up-regulated by 2.5-fold normalized to the model group (P<0.05).

CONCLUSION

ESP extract effectively alleviates the symptoms of PSYD and relieves PSYD-induced diarrhea by improving AQP3 synthesis in the colon.