Effects Of Homocysteine On The Expression Of The Thrombomodulin And The Endothelial Protein C Receptor In The Experimental Colitis Rats

Background: In recent years,the morbidity of Ulcerative colitis(UC)has increased significantly in China,but its exact pathogenesis is complex.In the pathophysiology of inflammatory bowel disease(IBD),intestinal mucosa microvascular endothelial cells regulate intestinal inflammation and coagulation mechanism by protein C(PC)pathway,but the molecular expression and function of PC pathway components during the pathogenesis of IBD is still unknown.Homocysteine(Hcy)is a type of sulfur-containing amino acid which plays a vital role in the thrombosis of cardiovascular disease by restraining the expression of PC components and reducing the effect of anticoagulation and anti-inflammation of PC.In view of the higher level of Hcy in intestine mucosa of IBD patients and the important role of microthrombosis in the pathological process of IBD,whether Hcy can affect the related factors during the micro thrombosis formation of intestinal mucosa,and then aggravate the colonic inflammatory response is not clear.We are aimed to explore the effect of Hcy on expression of soluable thrombomodulin(s TM),PC,free protein S(f PS)and endothelial protein C receptor(EPCR)in intestine mucosa of experimental UC rats,then further explain the pathogenesis and therapeutic target of ulcerative colitis by Hcy.Methods:UC rat model was prepared by enema with 2,4,6-three nitric acid(TNBS).SD rats are divided into 4groups which have 8 rats per group: Group A(control group):enema by NS& subcutaneous injection by NS;Group B(normal control+ Hcy injection group): enema by NS+ subcutaneous injection by Hcy;Group C(TNBS model group):enema by TNBS/ethyl alcohol+ subcutaneous injection by NS;Group D(TNBS model+Hcy injection): enema by TNBS/ethyl alcohol+ subcutaneous injection by Hcy;Keep record of consistency of defecation and weight change and inspect the incidence of hematochezia by visual inspection or dipstick and arrange DA.The levels of s TM,PC,f PS of UC plasma and colon mucosa homogenate were determined by ELISA.The expression of TM and EPCP m RNA and the expression of TM and EPCP in colon tissue were determined by RT-PCR and Immunohistochemistry respectively.Result: The weight of rats in TNBS model group were obviously reduced and DAI score was increased compared with normal control group(P<0.05).What's more,the rats in TNBS model group present hematochezia by visual inspection in various degrees.The level of Hcy in UC plasma and colon tissue of TNBS model group was obviously increased compared with normal control group(P<0.01).The level of Hcy in UC plasma and colon tissue in TNBS model& Hcy injection group was obviously increased compared with normal control group& Hcy injection group(P<0.01).Compared with normal group,the levels of s TM& PC of colon mucosa in TNBS model group are obviously decreased(P<0.05).The level of f PS in two groups were not reach the difference(P>0.05).Compared with TNBS model,the levels of s TM,PC& f PS of colon mucosa in TNBS model& Hcy injection are obviously decreased(P<0.05).The differences of TM& EPCR m RNA expression in the colon mucosa of each group have the statistics significance(P<0.05).Conclusions: Hcy affect the functions and inflammation of intestinal mucosa microvascular endothelial cells of colon mucosa by reducing the expression of PC in colon mucosa of UC and aggravates the injury of colon mucosa,suggesting that Hcy may affect the anticoagulation and anti-inflammation of PC and cause a prothrombotic related intestinal microcirculation.