| Colchicine is an alkaloid extracted from the seeds and bulbs of the Colchicum autumnale plant,which has the ability to interfere with the cellular chromatin system and tubulin depolymerization and is used clinically in the treatment of Beh?et’s disease,familial Mediterranean fever,cardiovascular disease,and some auto-inflammatory diseases.Colchicine is also listed as the drug of choice for the treatment of gouty arthritis,but it has a very narrow therapeutic window and tends to cause toxicity in the body,and it can cause severe adverse effects in the gastrointestinal tract,mainly nausea,vomiting,and diarrhea,even when taken at recommended doses.The strong gastrointestinal toxicity of colchicine has,to a certain extent,hindered the expansion of its use in clinical practice and reduced the enthusiasm of patients to use it in the treatment of their diseases.However,the mechanism of colchicine causing severe gastrointestinal toxicity remains unclear.The gastrointestinal tract is an important place for colchicine absorption and utilization.There are tens of thousands of microorganisms living in the gastrointestinal tract,which are involved in the growth and development,immune regulation,mucosal integrity maintenance,and metabolic regulation of the host.It has been reported that drugs can alter the composition,diversity,and function of gastrointestinal microorganisms,which in turn can alter the biological activity,bioavailability,efficacy,and toxicity of drugs through chemical modifications or enzymatic reactions.In order to further understand the toxicity and mechanism of colchicine in gastrointestinal tract,we used mice as experimental animals and continuously gavaged them with colchicine at doses of 0.1,0.5,and 2.5 mg/kg/day for one week to construct diarrhea model.The interactions between colchicine and gastrointestinal microorganisms in mice and its toxic effects on the biogeographic structure attached to the microbial community were systematically studied by means of behavioral,histology,molecular biology,microbiome,and metabolomics.The main research results and conclusions are as follows:1.Basic toxicity of colchicine to mice:(1)Colchicine treatment reduced the body weight and daily feed intake of mice,and 2.5 mg/kg/day treatment had the most significant effects.(2)All three doses of colchicine treated mice showed different degrees of hair removal,and the movement ability of mice also decreased significantly,mainly in the total distance and average speed of mice.(3)Colchicine treatment did not cause significant changes in the organ indexes of the heart,liver,spleen,lung,and kidney of mice,but caused significant increases in the organ indexes of the stomach,stomach enlargement and food accumulation.(4)The doses of 0.5 mg/kg/day and 2.5mg/kg/day caused diarrhea in mice,among which 2.5 mg/kg/day caused the most obvious diarrhea,which showed that fecal water content and frequency of defecation increased significantly.2.Effects of colchicine on the structure of the gastrointestinal mucosa in mice:(1)Colchicine treatment significantly reduced the gastric emptying rate and delayed food transport to the intestine.(2)Colchicine treatment caused mucosal injury of stomach,duodenum,ileum,and colon.(3)Colchicine treatment caused a significant increase in the intestinal barrier biomarkers DAO and LPS in the serum of mice,suggesting that colchicine treatment destroyed the intestinal barrier of mice.(4)The mRNA expression of tight junction proteins Zo-1,Claudin-1,and Occludin in the ileum and colon of mice decreased significantly after colchicine treatment,which further indicated that colchicine treatment could destroy intestinal barrier and increase intestinal permeability.(5)Colchicine treatment significantly inhibited the gastrointestinal inflammatory response of mice,which was mainly reflected in the decreased mRNA expressions of pro-inflammatory cytokines IL-1β,IL-6,and TNF-α in stomach,duodenum,ileum,and colon.3.Effects of colchicine on gastrointestinal microorganisms in mice:(1)Colchicine treatment significantly reduced the microbial diversity in the gastrointestinal tract of mice,and showed dose-dependent characteristics.(2)Colchicine treatment changed the composition of gastrointestinal microorganisms,and the relative abundance of most bacteria decreased significantly,which made colchicine show antibacterial potential.(3)Colchicine treatment changed the function of gastrointestinal microorganisms in mice.(4)The effect of colchicine on the microbial community structure in the stomach was significantly stronger than that in the gut,showing a dose-effect relationship.(5)Some microorganisms can be used as biomarkers to distinguish the control group from the colchicine-induced diarrhea group,and the changes of these microorganisms are closely related to colchicine-induced diarrhea.4.Effects of colchicine on intestinal metabolic homeostasis in mice:(1)Colchicine treatment disrupted metabolic homeostasis in the mouse gut,resulting in fluctuations of about one eighth(180/1445)metabolites,among which 116 metabolites were significantly up-regulated and 64 metabolites were significantly down-regulated.These fluctuations of differential metabolites were mainly concentrated in amino acid metabolism,lipid metabolism,nucleic acid metabolism,digestive system,signal transduction,and other metabolic pathways.The metabolic pathways were significantly enriched in Ras signaling pathway,Rap1 signaling pathway,phospholipase D signaling pathway,and α-linolenic acid metabolic pathway.The metabolic pathways that are more enriched for differential metabolites are phenylalanine,tyrosine and tryptophan biosynthesis and metabolism pathways,purine metabolism pathway,and bile secretion pathway.(2)By mapping the interaction network between differential metabolites and metabolic pathways,we found that c AMP,Adenosine 5’-monophosphate,GDP,Inositol,and Cortisol play a core role in metabolic disorders caused by colchicine,and the changes of the five core metabolites were significantly correlated with each other.(3)cAMP,Adenosine 5’-monophosphate,GDP,Inositol,and Cortisol could be used as biomarkers to distinguish between control group and colchicine-induced diarrhea group.5.Joint analysis of microbiome and metabolomics: Colchicine induced gastrointestinal microbial homeostasis in mice was closely related to intestinal metabolic disorders.6.Toxic effects of colchicine on bile acid metabolism in mice:(1)Colchicine treatment significantly inhibited the mRNA expression levels of regulatory factors(Cyp7a1,Cyp8b1,Cyp7b1,and Cyp27a1)related to bile acid biosynthesis in liver tissue.In addition,the mRNA expression levels of bile acid transporters(Ntcp,Oatp1,Mrp2,Ibabp,Mrp3,Osta,and Ostb)in liver and ileum were also significantly inhibited.(2)Colchicine treatment significantly inhibited the mRNA expression levels of FXR and its downstream target genes Shp,Lrh1,and Fgf15 in liver and ileum,and affected the feedback regulation of bile acids.(3)The inhibition of bile acid transport proteins in ileal and hepatic tissues by colchicine affected the recycling of bile acids in the intestine and their reuptake in the liver,resulting in the accumulation of 76% of bile acids in the colon,and significant accumulation of LCA,isoLCA,12-ketoLCA,HDCA,and GCA.Conclusion: Colchicine treatment could destroy the gastrointestinal mucosal structure on which gastrointestinal microorganisms depend for survival,increase intestinal permeability,inhibit inflammatory response,and then cause the migration of dependent microorganisms,community structure disorders,and metabolic disorders.And the accumulation of bile acids in the colon is an important cause of diarrhea.In this study,the gastrointestinal toxicity induced by colchicine and the potential mechanism of gastrointestinal adverse reactions were systematically studied through multi-omics analysis,which broadened the theoretical basis of colchicine toxicology,enhanced people’s understanding of the interaction between drugs and the host microbiome,and provided a new idea for improving the efficacy of colchicine by regulating the host microbiome. |
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