| Background and Aims:Symbiotic bacteria Faecalibacterium prausnitzii (F. prausnitzii) has received extensive attention recently, which was decreased in the gut of patients with inflammatory bowel disease (IBD). Meanwhile, F. prausnitzii has a certain correlation with the development of IBD. The aims of present study were to investigate the protective effects of F. prausnitzii and its products on rat colitis induced by2,4,6-trinitrobenzene sulfonic acid (TNBS) and to observe the inhibitive effects and mechanisms on cytokines produced by in vitro cells.Methods:40Sprague-Dawley (SD) rats were randomly divided into control group, colitis group, supernatant group, F. prausnitzii group and B. longum (Bifidobacterium longum) group. The rats of last four groups were administered intragastrically with PBS buffer, the supernatant of F. prausnitzii, live F. prausnitzii and live B. longum, respectively5days before and1day after TNBS treated. Rats were killed48h after TNBS treated. The rats were to perform the examination for colon pathology and fecal short-chain fatty acids (SCFA) using gas chromatography. The plasma level of interleukin-10(IL-10), interleukin-12(IL-12), interleukin-17(IL-17) and interleukin-23(IL-23) was measured by ELISA. The expression of intestinal IL-17was detected by immunohistochemistry.In Vitro study,the rat spleen cells were co—cultured with bone marrow DC cells(BMDC)or cytokines(transforming growth factor p,TGF-p pluS IL一6)with PBS buffer,the supernatant ofF prausnitzii,F prausnitzii,B.longum and butyrate,respectively.Besides,humen peripheral blood mononuclear cells (PBMCs) were also co—cultured with the medium of F prausni,tzii different concentrated supernatant of F prausnitzii,F prausnitzii and B.,longum,respectively. And then the levels of IL一10,IL一12,IL一17,IL一23in cell culure medium were detected by ELI SA.Results:Compared with the control group,the rats of colitis group suffered serious weight loss[(7.14士7.54)％vs(一4.88士4.05)％],the intestinal pathology score increased [(1士0.99) VS (3.34士0-38)], and the concentration of IL一17in plasma[(16.61±2.45)pg／ml VS(20.47士1.45)pg／ml]and expression in colon[(O.83士O.98)VS(5.14士0.9)]increased(all P<O.05),respectively.While compared with the colitis group,the supernatant could significantly inhibit the weight loss[(O.5土4.34)％],decrease lower colon pathology score(2.5±0.44),redlice the expression ofIL一17in plasma[(17.54士1.51)pg／ml]and in colon(2.86士0.69)(all P <0.05).Compared with the control group,total SCFA content in the colitis group rats was decreased[(34.13土1O.97)¨mollg vs(30.89士9.12)μmol／g],but there was no significant difference(P=0.53).Butyric acid proportion in the colitis group rats was decreased compared to control group [(0.19士0.09) VS (0.11士O.02)](P<0.01). Compared with the colitis group,butyric acid proportion[(O.11士0.02)VS(0.2士O.05)], the content of butyric acid[(4.37土2.94)¨molg vs(9.98士4.43)μmol／g]and total SCFA[(30.89士9.12)μmolg vs(43.97士5.6)"molg]in the F prausnitzii,group were increased(all P<O.05).Compared with the control group(cont),BMDC and cytokine(TGF-βplus IL一6) significantly promoted the expression of IL-17in cell culture medium in PBS groups(PBS)[(182.2±89.12)pg／ml VS(309.24±2l-3)pg／ml,(17.36±O.38)pg／ml VS(20.54±2.12)pg／ml](P<O.05),whereas,the supernatant(Fps, supematant group)could significantly inhibit IL-17expression induced by BMDC and cytokine respectively in the cell culture medium [(309.24±21.3) pg/ml vs (58.11±19.2) pg/ml,(20.54±2.12) pg/ml vs (17.25±0.42) pg/ml](P<0.05). In the PBMC test, IL-10level and IL-10/IL-12ratio in different concentrated supernatant groups were significantly increased with a dose-dependent manner compared to F. prausnitzii medium group (medium). One time concentrated supernatant (1supernatant) showed the highest IL-10level and IL-lO/IL-12ratio [(3.52±2.08)pg/ml vs (768.95±263.57) pg/ml,(3.99±2.43vs914.68±579.67)](P＜0.001).Conclusions:Both F. prausnitzii and its products could regulate the secretion of inflammation-related cytokines including IL-17to ameliorate colitis in rats. But the effects induced by F. prausnitzii and its products might be different which F. prausnitzii played the role in the Thl7effective stage by inhibiting IL-23secretion to decrease the IL-17-mediated inflammation, whereas, the products of F. prausnitzii played the roles in the differentiation stage of Thl7by reducing the amount of Thl7cells to decrease the inflammatory response. The effects on anti-inflammatory of F. prausnitzii product displayed stronger than that of F. prausnitzii. The similar effects might exist in human diseases. |
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