本试验旨在研究琥珀酸对产肠毒素大肠杆菌(ETEC) K88感染小鼠肠道炎症的影响及其机制。选取40只7周龄C57BL/6J雄性小鼠,随机分成4组(每组10只):正常对照组(NC组)、琥珀酸组(SUC组)、大肠杆菌组(ETEC组)和琥珀酸+大肠杆菌组(SUC+ETEC组)。4组小鼠均饮用去离子水,SUC组和SUC+ETEC组小鼠在饮水中添加20 mmol/L的琥珀酸。试验第4天,ETEC组和SUC+ETEC组每天灌胃浓度1×1010 CFU/mL的ETEC K88菌液0.2 mL,持续3 d,恢复1 d。适应期7 d,试验期8 d。结果表明:1)与NC组相比,ETEC组造模后体重显著降低(P<0.05);与ETEC组相比,SUC+ETEC组造模后体重以及空肠绒毛高度和绒毛高度/隐窝深度显著升高(P<0.05)。2)与NC组相比,ETEC组血浆和空肠中肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)浓度显著升高(P<0.05),白细胞介素-10(IL-10)和白细胞介素-4(IL-4)浓度显著降低(P<0.05);与ETEC组相比,SUC+ETEC组血浆中IL-6浓度显著降低(P<0.05),空肠中TNF-α和IL-6浓度显著降低(P<0.05),空肠中IL-10浓度显著升高(P<0.05)。3)与NC组相比,ETEC组血浆中内毒素、二胺氧化酶(DAO)和D-乳酸(D-LA)浓度显著升高(P<0.05);与ETEC组相比,SUC+ETEC组血浆中内毒素和D-LA浓度显著降低(P<0.05)。4)与NC组相比,ETEC组空肠中密封蛋白-1(Claudin-1)和咬合蛋白(Occludin)的表达水平显著降低(P<0.05);与ETEC组相比,SUC+ETEC组空肠中Claudin-1和Occludin的表达水平显著升高(P<0.05)。综上所述,饮水添加琥珀酸可增强小鼠空肠紧密连接相关蛋白表达,改善肠道通透性,调节炎症因子分泌,缓解ETEC K88感染引起的肠道炎症。
This experiment was conducted to investigate the effects of succinic acid on intestinal inflammation of mice infected with enterotoxigenic Escherichia coli (ETEC) K88 and its mechanism. Forty 7-week-old C57BL/6J male mice were selected and randomly divided into 4 groups (10 replicates in each group): normal control group (NC group), succinic acid group (SUC group), Escherichia coli group (ETEC group) and succinic acid+Escherichia coli group (SUC+ETEC group). Mice in four groups were all drank deionized water, and mice in SUC group and SUC+ETEC group added 20 mmol/L succinic acid in drinking water. On day 4 of the experiment, mice in ETEC group and SUC+ETEC group were gavage administration 0.2 mL of ETEC K88 bacterial solution with a concentration of 1×1010 CFU/mL every day for 3 d and recovered for 1 d. The adaptation period was 7 days, and the experimental period was 8 days. The results showed as follows: 1) compared with NC group, the body weight after modeling of ETEC group was significantly decreased (P<0.05); compared with ETEC group, the body weight after modeling and jejunal villus height and villus height/crypt depth of SUC+ETEC group were significantly increased (P<0.05). 2) Compared with NC group, the concentrations of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in plasma and jejunum of ETEC group were significantly increased (P<0.05), and the interleukin-10 (IL-10) and interleukin-4 (IL-4) concentrations were significantly decreased (P<0.05); compared with ETEC group, the plasma IL-6 concentration of SUC+ETEC group was significantly decreased (P<0.05), the concentrations of TNF-α and IL-6 in jejunum were significantly decreased (P<0.05), and the jejunal IL-10 concentration was significantly increased (P<0.05). 3) Compared with NC group, the concentrations of endotoxin, diamine oxidase (DAO) and D-lactic acid (D-LA) in plasma of ETEC group were significantly increased (P<0.05); compared with ETEC group, the concentrations of endotoxin and D-LA in plasma of SUC+ETEC group were significantly decreased (P<0.05). 4) Compared with NC group, the expression levels of Claudin-1 and Occludin in jejunum of ETEC group were significantly decreased (P<0.05); compared with ETEC group, the expression levels of Claudin-1 and Occludin in jejunum of SUC+ETEC group were significantly increased (P<0.05). In conclusion, adding succinic acid to drinking water can enhance the expression of tight junction protein in jejunum, improve the intestinal permeability, regulate the secretion of inflammatory factors, and alleviate the intestinal inflammation in mice caused by ETEC K88 infection.
[1] LI X Y,WANG L L,ZHEN Y H,et al.Chicken egg yolk antibodies (IgY) as non-antibiotic production enhancers for use in swine production:a review[J].Journal of Animal Science and Biotechnology,2015,6(1):40.
[2] LUPPI A.Swine enteric colibacillosis:diagnosis,therapy and antimicrobial resistance[J].Porcine Health Management,2017,3:16.
[3] FLECKENSTEIN J M,HARDWIDGE P R,MUNSON G P,et al.Molecular mechanisms of enterotoxigenic Escherichia coli infection[J].Microbes and Infection,2010,12(2):89-98.
[4] JOFFRÉ E,VON MENTZER A,SVENNERHOLM A M,et al.Identification of new heat-stable (STa) enterotoxin allele variants produced by human enterotoxigenic Escherichia coli(ETEC)[J].International Journal of Medical Microbiology,2016,306(7):586-594.
[5] YI H B,ZHANG L,GAN Z S,et al.High therapeutic efficacy of Cathelicidin-WA against postweaning diarrhea via inhibiting inflammation and enhancing epithelial barrier in the intestine[J].Scientific Reports,2016,6(1):25679.
[6] SARGEANT H R,SHAW M A,ABUOUN M,et al.The metabolic impact of zinc oxide on porcine intestinal cells and enterotoxigenic Escherichia coli K88[J].Livestock Science,2010,133(1/2/3):45-48.
[7] TRETTER L,PATOCS A,CHINOPOULOS C.Succinate,an intermediate in metabolism,signal transduction,ROS,hypoxia,and tumorigenesis[J].Biochimica et Biophysica Acta,2016,1857(8):1086-1101.
[8] TANNAHILL G M,CURTIS A M,ADAMIK J,et al.Succinate is an inflammatory signal that induces IL-1β through HIF-1α[J].Nature,2013,496(7444):238-242.
[9] LEI W W,REN W W,OHMOTO M,et al.Activation of intestinal tuft cell-expressed Sucnr1 triggers type 2 immunity in the mouse small intestine[J].Proceedings of the National Academy of Sciences of the United States of America,2018,115(21):5552-5557.
[10] NADJSOMBATI M S,MCGINTY J W,LYONS-COHEN M R,et al.Detection of succinate by intestinal tuft cells triggers a type 2 innate immune circuit[J].Immunity,2018,49(1):33-41.e7.
[11] XU C L,YAN S Q,GUO Y,et al.Lactobacillus casei ATCC 393 alleviates enterotoxigenic Escherichia coli K88-induced intestinal barrier dysfunction via TLRs/mast cells pathway[J].Life Sciences,2020,244:117281.
[12] LIU B,LIU Q M,LI G L,et al.The anti-diarrhea activity of red algae-originated sulphated polysaccharides on ETEC-K88 infected mice[J].RSC Advances,2019,9(5):2360-2370.
[13] HAN X B,DING S J,MA Y,et al.Lactobacillus plantarum and Lactobacillus brevis alleviate intestinal inflammation and microbial disorder induced by ETEC in a murine model[J].Oxidative Medicine and Cellular Longevity,2021,2021:6867962.
[14] WANG K,LIAO M F,ZHOU N,et al.Parabacteroides distasonis alleviates obesity and metabolic dysfunctions via production of succinate and secondary bile acids[J].Cell Reports,2019,26(1):222-235.e5.
[15] ZHU J J,GAO M X,ZHANG R L,et al.Effects of soybean meal fermented by L.plantarum,B.subtilis and S.cerevisieae on growth,immune function and intestinal morphology in weaned piglets[J].Microbial Cell Factories,2017,16(1):191.
[16] MONTAGNE L,CAVANEY F S,HAMPSON D J,et al.Effect of diet composition on postweaning colibacillosis in piglets[J].Journal of Animal Science,2004,82(8):2364-2374.
[17] MOOR A E,HARNIK Y,BEN-MOSHE S,et al.Spatial reconstruction of single enterocytes uncovers broad zonation along the intestinal villus axis[J].Cell,2018,175(4):1156-1167.e15.
[18] LI X,MAO M Y,ZHANG Y N,et al.Succinate modulates intestinal barrier function and inflammation response in pigs[J].Biomolecules,2019,9(9):486.
[19] DIAO H,JIAO A R,YU B,et al.Gastric infusion of short-chain fatty acids can improve intestinal barrier function in weaned piglets[J].Genes&Nutrition,2019,14:4.
[20] SUN X,CUI Y L,SU Y Y,et al.Dietary fiber ameliorates lipopolysaccharide-induced intestinal barrier function damage in piglets by modulation of intestinal microbiome[J].mSystems,2021,6(2):e01374-20.
[21] MACIAS-CEJA D C,ORTIZ-MASIÁ D,SALVADOR P,et al.Succinate receptor mediates intestinal inflammation and fibrosis[J].Mucosal Immunology,2019,12(1):178-187.
[22] GERBE F,SIDOT E,SMYTH D J,et al.Intestinal epithelial tuft cells initiate type 2 mucosal immunity to helminth parasites[J].Nature,2016,529(7585):226-230.
[23] BANDO J K,GILFILLAN S,DI LUCCIA B,et al.ILC2s are the predominant source of intestinal ILC-derived IL-10[J].Journal of Experimental Medicine,2020,217(2):e20191520.
[24] DRUREY C,LINDHOLM H T,COAKLEY G,et al.Intestinal epithelial tuft cell induction is negated by a murine helminth and its secreted products[J].The Journal of Experimental Medicine,2022,219(1):e20211140.
[25] HARBER K J,DE GOEDE K E,VERBERK S G S,et al.Succinate is an inflammation-induced immunoregulatory metabolite in macrophages[J].Metabolites,2020,10(9):372.
[26] KEIRAN N,CEPERUELO-MALLAFRÉ V,CALVO E,et al.SUCNR1 controls an anti-inflammatory program in macrophages to regulate the metabolic response to obesity[J].Nature Immunology,2019,20(5):581-592.
[27] SMIRNOVA M G,BIRCHALL J P,PEARSON J P.TNF-alpha in the regulation of MUC5AC secretion:some aspects of cytokine-induced mucin hypersecretion on the in vitro model[J].Cytokine,2000,12(11):1732-1736.
[28] SERENA C,CEPERUELO-MALLAFRÉ V,KEIRAN N,et al.Elevated circulating levels of succinate in human obesity are linked to specific gut microbiota[J].The ISME Journal,2018,12(7):1642-1657.
[29] OSUNA-PRIETO F J,MARTINEZ-TELLEZ B,ORTIZ-ALVAREZ L,et al.Elevated plasma succinate levels are linked to higher cardiovascular disease risk factors in young adults[J].Cardiovascular Diabetology,2021,20(1):151.
[30] CAPALDO C T,POWELL D N,KALMAN D.Layered defense:how mucus and tight junctions seal the intestinal barrier[J].Journal of Molecular Medicine,2017,95(9):927-934.
[31] KUO W T,ZUO L,ODENWALD M A,et al.The tight junction protein ZO-1 is dispensable for barrier function but critical for effective mucosal repair[J].Gastroenterology,2021,161(6):1924-1939.
[32] POPE J L,BHAT A A,SHARMA A,et al.Claudin-1 regulates intestinal epithelial homeostasis through the modulation of Notch-signalling[J].Gut,2014,63(4):622-634.
[33] DÖRFEL M J,HUBER O.Modulation of tight junction structure and function by kinases and phosphatases targeting occludin[J].Journal of Biomedicine and Biotechnology,2012,2012:807356.
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