Objective:To investigate the immunological mechanism by which grifola frondosa extract improves colonic tissue inflammation in rats with ulcerative colitis(UC)through the sphingosine kinase 1(SPHK1)/sphingosine-1-phosphate(S1P)signaling pathway.Methods:Forty male SD rats were randomly divided into five groups:blank group,model group,sulfasalazine treatment group(SASP group),grifola frondosa extract treatment group(GF group),and sulfasalazine combined with grifola frondosa extract treatment group(SASP+GF group).UC model was established using a 3%dextran sulfate sodium(DSS)free drinking method.After one week,each treatment group received sulfasalazine 0.3 g/(kg·d),grifola frondosa extract 10 mg/(kg·d),and combination of both drugs by gavage.During the experiment,the general condition of the rats was observed,the disease activity index(DAI)score was re-corded and the protein content and positive expression levels of SPHK1,S1P,tumor necrosis factor receptor-associated factor 2(TRAF2)and TNF-α in rat colon tissue were detected by immunohistochemistry.mRNA and protein expression levels of SPHK1,S1P,TRAF2 and TNF-α in rat colon tissue were measured by RT-qPCR and Western blot.Results:Compared with the blank group,the general condition of the model group rats were poor,the DAI score was significantly increased,and the protein positive expres-sion,mRNA and protein expression levels of SPHK1,S1P,TRAF2 and TNF-α in colon tissue were significantly increased(P<0.01).Compared with the model group,the general condition of the rats in each treatment group improved significantly,the DAI score was decreased(P<0.01),and the positive expression of each target protein was significantly reduced(P<0.01),especially in the GF group and SASP+GF group;the mRNA and protein expression levels of SPHK1 and TRAF2 were reduced to varying degrees(P<0.01 or P<0.05),while the mRNA and protein expression levels of S1P and TNF-α only decreased significantly in the GF group and SASP+GF group(P<0.01).Compared with the SASP group,the GF group only showed a decrease in SPHK1 protein expression,TNF-α mRNA,and protein expression levels,while the SASP+GF group showed significant reductions in all targets(P<0.01 or P<0.05).Compared with the GF group,the SASP+GF group showed significant reductions in SPHK1 protein positive expression and content,S1P mRNA expression levels,and TNF-α protein content(P<0.05 or P<0.01).Conclusion:Grifola frondosa extract may alleviate co-lonic tissue inflammation in rats with UC by inhibiting the activation of the SPHK1/S1P pathway,restoring intestinal mucosal barrier function,and improving symptoms of UC.

Objective:To investigate the immunological mechanism by which grifola frondosa extract improves colonic tissue inflammation in rats with ulcerative colitis(UC)through the sphingosine kinase 1(SPHK1)/sphingosine-1-phosphate(S1P)signaling pathway.Methods:Forty male SD rats were randomly divided into five groups:blank group,model group,sulfasalazine treatment group(SASP group),grifola frondosa extract treatment group(GF group),and sulfasalazine combined with grifola frondosa extract treatment group(SASP+GF group).UC model was established using a 3%dextran sulfate sodium(DSS)free drinking method.After one week,each treatment group received sulfasalazine 0.3 g/(kg·d),grifola frondosa extract 10 mg/(kg·d),and combination of both drugs by gavage.During the experiment,the general condition of the rats was observed,the disease activity index(DAI)score was re-corded and the protein content and positive expression levels of SPHK1,S1P,tumor necrosis factor receptor-associated factor 2(TRAF2)and TNF-α in rat colon tissue were detected by immunohistochemistry.mRNA and protein expression levels of SPHK1,S1P,TRAF2 and TNF-α in rat colon tissue were measured by RT-qPCR and Western blot.Results:Compared with the blank group,the general condition of the model group rats were poor,the DAI score was significantly increased,and the protein positive expres-sion,mRNA and protein expression levels of SPHK1,S1P,TRAF2 and TNF-α in colon tissue were significantly increased(P<0.01).Compared with the model group,the general condition of the rats in each treatment group improved significantly,the DAI score was decreased(P<0.01),and the positive expression of each target protein was significantly reduced(P<0.01),especially in the GF group and SASP+GF group;the mRNA and protein expression levels of SPHK1 and TRAF2 were reduced to varying degrees(P<0.01 or P<0.05),while the mRNA and protein expression levels of S1P and TNF-α only decreased significantly in the GF group and SASP+GF group(P<0.01).Compared with the SASP group,the GF group only showed a decrease in SPHK1 protein expression,TNF-α mRNA,and protein expression levels,while the SASP+GF group showed significant reductions in all targets(P<0.01 or P<0.05).Compared with the GF group,the SASP+GF group showed significant reductions in SPHK1 protein positive expression and content,S1P mRNA expression levels,and TNF-α protein content(P<0.05 or P<0.01).Conclusion:Grifola frondosa extract may alleviate co-lonic tissue inflammation in rats with UC by inhibiting the activation of the SPHK1/S1P pathway,restoring intestinal mucosal barrier function,and improving symptoms of UC.