Effects Of Homocysteine On Intestinal Mucosal Inflammation Of Inflammatory Bowel Disease And Its Mechanism

Backgroud The current pathogenesis of Inflammatory bowel disease(IBD)is unknown,the inflammatory damage caused by the abnormal reaction of intestinal mucosal immune system plays an important role in the pathogenesis of IBD.Immune cells produce inflammatory mediators,such as LTs,PGs,histamine and so on,and cytokines forme the immune regulation system imbalance may be the key to causing intestinal mucosal pathological damage.The study found that the levels of PGE2 and LTE4 in urine of patients with UC were higher than that of normal control group,and disease activity period were higher than the remission period.Homocysteine is a kind sulfur-containing amino acid,which can cause cell damage and an independent risk factor for the onset of atherosclerosis,and gradually found that also involved in the liver,kidney,lung and other organs fibrosis process.Studies have found elevated levels of plasma Hcy in IBD patients.In recent years,the relationship between Hcy and IBD pathogenesis has been gradually attracted attention.It is not yet clear whether Hcy aggravates intestinal inflammatory injury by promoting the secretion of inflammatory mediators such as LTE4 and PGE2.Thus,this study intends to detect the urinary levels of Hcy,PGE2 and LTE4 for clinical association analysis,to explore the correlation between Hcy and IBD intestinal injury.Objective To investigate the correlation between urinary Hcy,LTE4 and PGE2 levels in IBD patients by detecting changes of urinary Hcy,LTE4 and PGE2 in patients with inflammatory bowel disease.Methods Collected 99 patients diagnosed with IBD in our hospital from October 2015 to December 2016,including 66 cases CD and 33 cases UC patients,clinical data were collected, respectively.At the same time,10 cases of the healthy control group were selected with all normal results of medical biochemistry and imaging check in the near future,and nearly 1 month with no symptoms of gastrointestinal tract,the urinary levels of Hcy,LTE4 and PGE2 in IBD and healthy controls groups were detected by Enzyme-linked immunosorbent assay(ELISA)method,evaluation of disease activity and the correlation analysis between Hcy and LTE4 or PGE2.Results Compared with the normal control group(9.21±7.62ng/ml),the levels of Hcy in urine of patients with IBD,CD and UC were all significantly increased(20.60±12.87ng/ml,20.05±11.74ng/ml,21.71±15.02ng/ml;P<0.05).Compared with the normal control group(16.81±7.97ng/ml),the levels of LTE4 in urine of patients with IBD,CD and UC were all significantly increased(61.76±52.96ng/ml,61.31±54.49ng/ml,66.17±50.28ng/ml;P <0.05).Compared with the normal control group(0.59 ± 0.35 ng / ml),the levels of PGE2 in urine of patients with IBD,CD and UC were all significantly increased(5.64±2.37ng/ml,6.01±2.03ng/ml,4.88±2.81ng/ml;P <0.05).The urinary levels of Hcy,LTE4 and PGE2 in CD patients with different biological behavior were all no significant differences(P>0.05),in addition to the level of urinary PGE2 between B1(non-stenosis non-penetrating)or B2(narrow)and B3(penetrating)group(P<0.05).The urinary levels of Hcy,LTE4 and PGE2 in UC patients with different severity and lesions areas were all no significant differences(P>0.05),in addition to the level of urinary LTE4 between E2(left colon)and E3(extensive colon)group(P<0.05).The urinary levels of Hcy,LTE4 and PGE2 in IBD,CD and UC patients had a certain related trend,but no statistical differences.Conclusion The urinary levels of Hcy,LTE4 and PGE2 in IBD were elevated compared with normal population,suggesting that Hcy,LTE4 and PGE2 were related to IBD.Background Inflammatory bowel disease(IBD)is a gastrointestinal disease,and its incidence is increasing.However,the pathogenesis is not clear.Previous studies have found that IBD intestinal mucosal inflammation closely associate with 5-LOX and COX-2.In IBD inflammatory intestinal mucosa,the levels of LTs and PGs produced by 5-LOX and COX-2 were increased respectively.Homocysteine(Hcy)can lead to oxidative damage to cells and promote the release of inflammatory mediators.Hcy can activate nuclear factor NF-?B,causing the relevant inflammatory gene transcription and expression,involved in the development of inflammation.NF-?B is a transcription factor of the Rel family and participates in the regulation of immune and inflammatory responses.In the inflammatory state,NF-?B regulates the expression of 5-LOX and COX-2.A large amount of activated NF-?B in the intestinal mucosa epithelium cells of IBD patients,which is involved in the regulation of the production and release of IBD related inflammatory factors,and aggravating the intestinal inflammatory response.Hcy concentration in colonic mucosa increasing in IBD patients,and would further aggravate the pathological damage of colonic inflammation,but the specific mechanism that Hcy damages to IBD intestinal mucosa is yet not clear.Thus,the aim of this study is to investigate whether Hcy can regulate the expression of 5-LOX and COX-2 to increase the levels of LTs and PGE2 secretion by promoting the expression of NF-?B on the basis of the experimental colitis rats model with high homocysteine,aggravating colon inflammation.Objective To investigate Hcy can regulate the expression of 5-LOX and COX-2 by promoting the transcription of NF-?B,causing the levels of LTs and PGs rising,exacerbating the process of colon inflammation.Methods Rats colitis model was prepared by 2,4,6-trinitrobenzene sulfonic acid(TNBS)/ ethanol enema,and hyperhomocysteinemia(HHcy)model was induced by subcutaneous injection of homocysteine.SD rats were divided into four groups: group A(normal control group): NS enema + NS subcutaneous injection;group B(TNBS model group): TNBS / ethanol solution enema + NS subcutaneous injection;group C(normal control group + Hcy injection group): NS enema + Hcy subcutaneous injection;group D(TNBS model group + Hcy injection group): TNBS / ethanol solution enema + Hcy subcutaneous injection.The levels of LTs(LTB4,LTC4,LTD4,LTE4)and PGE2 in colon homogenate of rats were measured by ELISA.The expression of 5-LOX,COX-2 and NF-?B m RNA in colonic mucosa of rats was measured by RT-q PCR.Results Compared with the normal group,the levels of LTs and PGs in rats colonic homogenate with model group and normal + Hcy injection group all were higher,the relative expression of COX-2?5-LOX and NF-?B m RNA in rats colonic mucosa all were higher.Compared with the TNBS model group,the levels of LTs and PGs in rats colonic homogenate with TNBS model + Hcy injection group were higher,the relative expression of COX-2,5-LOX and NF-?B m RNA in rats colonic mucosa were higher,the differences were statisticallysignificant(p<0.05).Conclusion Hcy regulates the expression of COX-2 and 5-LOX probably by promoting the transcription of NF-?B,causing the levels of LTs and PGs rising,ultimately exacerbating the process of colon inflammation.Background Inflammatory bowel disease(IBD)is a chronic inflammatory disease that occurs in the digestive tract,including Crohn's disease(CD)and ulcerative colitis(UC).It is believed that the activation of nuclear factor kappa B(nuclear factor-kappa B,NF-kappa B)occupies an important position in the development of IBD.IBD patients have an elevated Hcy level in plasma.Hcy can activate NF-?B.It exists a large number of activated NF-?B in intestinal mucosal macrophages and epithelial cells with IBD patients,NF-?B activation can promote 5-LOX and COX-2 expression.5-LOX and COX-2 are the key enzymes to generate LTE4 and PGE2,respectively.The levels of both LTE4 and PGE2 were significantly elevated in the intestinal mucosa with IBD patients.Therefore,by observing the effect of Hcy on the activity of NF-?B and the secretion of LTE4 and PGE2 in Caco-2 cells,it will be explored whether Hcy causes increased secretion of LTE4 and PGE2 or not by activating NF-?B,thereby aggravating intestinal epithelial cell inflammatory injury.Objective Treatment of Caco-2 cells with different concentrations of Hcy for different time to explore whether the activation of NF-?B by Hcy,causing increased secretion of LTE4 and PGE2,thereby aggravating intestinal epithelial cells inflammation injury.Methods The experiment was divided into blank control group and different concentrations Hcy groups.Caco-2 cells were incubated with Hcy after growing and cultured for 24 h.Hcy groups Caco-2 cells was treated ewith 10 umol / L,20 umol / L,50 umol / L and 100 umol / L Hcy;The normal control group cells was treated with equal cell culture medium.The change of NF-?B activity in the cells was detected by EMSA after the nucleoprotein was extracted at different time(1,3,6 h);simultaneously,the supernatant was collected and the levels of LTE4 and PGE2 were detected by ELISA.Results Compared with the normal control group,LTE4 and PGE2 levels in the Hcy treatment group increased(P<0.05).In different Hcy treatment groups,the levels of LTE4 and PGE2 in cells were gradually increased as the concentration of increased Hcy.In the 100umol/L Hcy treatment group,the level of Caco-2 cells generated LTE4 and PGE2 was time-dependent(0h,1h,3h,6h).Hcy can induce NF-?B activation,nuclear translocation and time-dependence(0h,1h,3h,6h).Conclusion Hcy may induce the increase of LTE4 and PGE2 synthesis by activating the NF-?B signaling pathway,and participate in the process of intestinal inflammatory injury.