AIM:To study the effect of angelica sinensis polysaccharide(ASP)on immunological colon injury and its mechanisms in rats.METHODS:Immunological colitis model of rats was inducedby intracolon enema with 2,4,6-trinitrobenzene sulfonicacid(TNBS)and ethanol.The experimental animals wererandomly divided into normal control,model control,5-aminosalicylic acid therapy groups and three doses of ASPtherapy groups.The 6 groups were treated intracolonicallywith normal saline,normal saline,5-aminosalicylic acid(100 mg·kg~(-1)),and ASP daily(8:00 am)at the doses of200,400 and 800 mg·kg~(-1)respectively for 21 days 7 dfollowing induction of colitis.The rat colon mucosa damageindex(CMDI),the histopathological score(HS),the score ofoccult blood test(OBT),and the colonic MPO activity wereevaluated.The levels of SOD,MDA,NO,TNF-α,IL-2 andIL-10 in colonic tissues were detected biochemically andimmunoradiometrically.The expressions of TGF-β and EGFin colonic tissues were also determined immunochemically.RESULTS:Enhanced colonic mucosal injury,inflammatoryresponse and oxidative stress were observed in colitis rats,which manifested as significant increases of CMDI,HS,OBT,MPO activity,MDA and NO contents,as well as the levels ofTNF-α and IL-2 in colonic tissues,although colonic TGF-βprotein expression,SOD activity and IL-10 content weresignificantly decreased compared with the normal control(P<0.01).However,these parameters were found to besignificantly ameliorated in colitis rats treated intracolicly withASP at the doses of 400 and 800 mg·kg~(-1)(P<0.05-0.01).Meantime,colonic EGF protein expression in colitis rats wasremarkably up-regulated.CONCLUSION: ASP has a protective effect on immunological colon injury induced by TNBS and ethanol enema in rats, which was propably due to the mechanism of antioxidation, immunomodulation and promotion of wound repair. AIM: To study the effect of angelica sinensis polysaccharide (ASP) on immunological colon injury and its mechanisms in rats. METHHODS: Immunological colitis model of rats was induced by intracolon enema with 2,4,6-trinitrobenzene sulfonic acid (TNBS) and ethanol. experimental animals were randomly divided into normal control, model control, 5-aminosalicylic acid therapy groups and three doses of ASP therapeutics. The 6 groups were treated intracolonically with normal saline, normal saline, 5-aminosalicylic acid (100 mg · kg -1) ) and ASP daily (8:00 am) at the doses of 200,400 and 800 mg · kg -1 for 21 days 7 dfollowing induction of colitis. The rat colon mucosa damage index (CMDI), the histopathological score ( HS), the score of blood test (OBT), and the colonic MPO activity wereevaluated.The levels of SOD, MDA, NO, TNF-α, IL-2 and IL-10 in colonic tissues were detected biochemically andimmunoradiometrically. -β and EGFin colonic tissues were also determined immunochemically .RESULTS: Enhanced colonic mucosal injury, inflammatory response and oxidative stress were observed in colitis rats, which manifested as significant increases in CMDI, HS, OBT, MPO activity, MDA and NO contents, as well as the levels of TNF-α and IL-2 in colonic tissues, although colonic TGF-βprotein expression, SOD activity and IL-10 content weresignificantly decreased compared with the normal control (P <0.01) .However, these parameters were found to be besignificantly ameliorated in colitis rats treated intracollyly with ASP at the doses of 400 and 800 mg · kg -1 (P <0.05-0.01) .Meantime, colonic EGF protein expression in colitis rats was markedly up-regulated.CONCLUSION: ASP has a protective effect on immunological colon injury induced by TNBS and ethanol enema in rats, which was propably due to the mechanism of antioxidation, immunomodulation and promotion of wound repair.