| BackgroundColon cancer is a refractory disease with the highest incidence of the top ten cancers in the world[1].Every year,the number of malignant tumor patients who die as a result of malignant colon cancer recurrence,related complications or poor prognosis is as high as 600,000,and its incidence is increasing year by year.There is an urgent need to strengthen primary prevention and standardized treatment of colon cancer.Effective control of etiology and prevention of precancerous lesions,fundamentally prevent and reduce the early occurrence of colon cancerColitis-associated cancer(CAC)is an important type of cancer.Inflammatory bowel disease(IBDs)has gradually developed into one of the important precancerous lesions of early colon cancer in China.How to effectively prevent and control the occurrence and development of IBDs is an important clinical and academic task of primary prevention of early colon cancer in China.At present,the pathogenesis of IBDs has not been fully elucidated[2].In recent years,studies have further found that intestinal lymphatic obstruction and dysfunction is one of the significant features of patients with IBDs,which can directly lead to the accumulation of inflammatory cells and aggravate intestinal inflammation.The loss of intestinal lymphatic vessels can significantly promote the further development of CAC induced by IBDs[3].Therefore,the treatment strategy based on promoting lymphangiogenesis of intestinal lymphatic vessels in patients with IBDs to improve inflammation has fully shown its good prospects for the treatment of IBDs and improving prognosisAt present,there are a large number of evidence-based medicine and basic research evidence that the imbalance of intestinal microecological is one of the important factors and mechanisms leading to the pathogenesis of colon cancer patients.Through the study of intestinal flora in patients with colon cancer,it has been found that it has changed significantly in the early stage of the disease[4].Clostridium butyricum(CB)is widely used in the treatment of human and animal diseases.Clostridium butyricum can ferment and decompose nutrients and produce a large amount of butyrate that can enter the colon,so as to alleviate the symptoms of patients with IBDs,and effectively inhibit the proliferation of colon cancer cells and promote their apoptosis,thus inhibiting the occurrence and development of colon cancer.A metabolic study related to colon cancer has preliminarily confirmed that the decrease of the content of butyric acid in the fecal extract of patients with IBDs is involved in the occurrence and development of IBDs inflammation[5].This study suggests that supplementation of CB can be used as an effective strategy for the prevention and treatment of IBDs.Based on the above gradually in-depth research results,we carried out further research on CB.The previous research results confirmed that the content of CB in patients with colon cancer was significantly lower than that in normal subjects.This result suggests that the change of CB content in patients may be related to the early process of colon cancer to some extent.In view of the fact that the loss of intestinal lymphatic vessels can promote the further development of colon cancer induced by IBDs,it is not clear whether supplementation of CB regulates the repair and function of lymphatic vessels under IBDs conditionsObjectiveWe used DSS-induced Balb/c mice to establish IBDs model,through in vitro experiments,given different interventions to verify whether CB promotes the repair of intestinal lymphatic vessels and its internal mechanismMethodsAnimal experiment:40 Balb/c mice were randomly divided into 4 groups:Control group(normal control group,n=10);CB group(Clostridium butyricum group,n=10);DSS group(DSS induced IBDs model group,n=10)and DSS+CB group(DSS combined with Clostridium butyricum group,n=10).The mice model of IBDs was induced by 3%DSS solution.Mice in DSS group and DSS+CB group drank 3%DSS solution freely for 8 days,while mice in Control group and CB group were given the same volume of water.On the 8th day,the four groups of drinking kettles were emptied and replaced with the same volume of water at the same time.On the 2nd,4th and 6th day of the experiment,mice in CB group and DSS+CB group were given intragastric administration of Clostridium butyricum solution[6]according to the concentration of 1000mg/(kg × rat × day),each group was given 200μL per day,and the same volume of aseptic phosphate buffer solution(PBS)was given to Control group and CB group.On the 8th,9th,10th and 11th day of the experiment,the mice in CB group and DSS+CB group were given intragastric administration of Clostridium butyricum solution with the optimal concentration of 5 × 106CFU/mL[7],each group was given 200 μL per day,and the same volume of aseptic PBS buffer was given to Control group and CB group.The mice were killed on the 12th day of the experiment.The clinical status,colon length from anus to ileocecum and disease activity index(DAI)were evaluated.Hematoxylin&Eosin(HE)staining was used to detect the inflammation of colonic tissue in model mice.Detection of lymphatic endothelial hyaluronic acid-1(LYVE-1)in colon tissue by immunohistochemical staining to determine the distribution of lymphatic vessels in colon tissue[9],and to detect the expression of vascular endothelial growth factor-C(VEGF-C)and vascular endothelial growth factor-D(VEGF-D)[10].Results1.Clostridium butyricum can effectively improve the symptoms of intestinal inflammation in mice with IBDs induced by DSS.We used weight changes,disease activity index,and colon length to assess the severity of inflammation.The results showed that compared with the Control group,the body weight of the DSS group was significantly lower and the disease activity index was significantly higher than that of the DSS group.Compared with the DSS group,the weight loss of the DSS+CB group was significantly improved and the disease activity index was significantly decreased(P<0.05).In addition,Clostridium butyricum could significantly reverse the shortening of colon length in IBDs mice induced by DSS(P<0.05)2.Clostridium butyricum attenuated DSS-induced colonic pathological damage and reduced colonic lymphocyte infiltration in IBDs.In DSS group,DSS induced severe injury of colon tissue,a large number of inflammatory cells infiltrated into mucosa and submucosa,crypt decreased or even disappeared,and intestinal epithelium was damaged.Compared with DSS group,significantly reduced pathological damage of colon tissue was observed in DSS+CB group.3.Clostridium butyricum repaired colonic lymphatic vessels of IBDs induced by DSS.By comparing the expression of LYVE-1 in intestinal tissues of mice in DSS group and DSS+CB group,it was found that Clostridium butyricum could significantly up-regulate the protein expression of LYVE-1,a marker molecule of lymphatic endothelium,after Clostridium butyricum acted on the colon tissue of IBDs model mice,suggesting that Clostridium butyricum can promote intestinal lymphatic vascular repair.4.Clostridium butyricum upregulated the expression of VEGF-C and VEGF-D in colonic tissue of IBDs induced by DSS.By comparing the expression of VEGF-C and VEGF-D in the intestinal tissue of DSS combined with DSS+CB group,it was found that Clostridium butyricum could significantly up-regulate the protein expression of VEGF-C and VEGF-D in the colon of IBDs mice.ConclusionsClostridium butyricum can promote the repair of lymphatic vessels in IBDs model mice,so that the broken and dysfunctional lymphatic vessels in the inflammatory site can be restored,and the inflammatory cells and lymphoid fluid gathered locally in the inflammatory site can be transported away from the inflammatory site through these new and functional lymphoid ducts,so as to alleviate the inflammatory state of IBDs in this site.MeaningsThe experimental results of this study will fill the gaps in the research on the mechanism of IBDs therapy,provide theoretical support for clinical use of probiotics to effectively control the occurrence and development of IBDs,find new targets for accurate treatment of IBDs,and provide promising new strategies and methods for primary prevention of colon cancer. |
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