The Change Of Intestinal Mucosal NBCe1 Expression And Function In Inflammatory Bowel Disease And DSS Enteritis

Object: 1.To study the expression of NBCe1 in inflammatory bowel disease and colon cancer.2.To study the expression of NBCe1 in a mouse model of colitis and the role of NBCe1 in mucous secretion.Methods: The expression and distribution of NBCe1 in colonic mucosal biopsies from IBD patients and cancer patients were detected by PCR and immunochemistry,respectively.C57bl/6 mice were subjected to 2.5%DSS to induce experimental colitis.The body weight changes,length of colon,disease activity index and histological activity index were tested.Transepithelial electrical resistance(TER)of colonic mucosa were examined.The expression level of NBCe1 was detected through PCR,immunoblotting and immunofluorescence.The basal current and variation of current after NBCe1 inhibitor and forskolin stimulation were detected by Ussing chamber.The intestinal mucosal thickness was detected by PA-ABS.The intestinal mucous secretion rate after S0859 stimulation was determined and the expression of mucin protein was tested.Result: 1.PCR analysis showed that the expression of NBCe1 in patients with IBD and colon cancer was significantly lower than that in normal subjects.The expression of NBCe1 in the paraneoplastic tissues was higher than that in the lesions.Immunohistochemical analysis showed that the expression of NBCe1 in CD patients was significantly downregulated than in healthy controls.2.Experiments colitis was established.DSS mice displayed weight loss,increased DAI score and increased HAI score,as well as shorter colon length.PCR analysis showed that the expression of NBCe1,and NBCn2 mRNA in DSS mice were significantly decreased with that of NBCe2,NBCn1 were increased in which NBCe1 had the highest level in the intestine.The results of immunoblotting showed that the protein expression of NBCe1 was significantly decreased in DSS mice compared with the control(P=0.0095).Consistent with abovementioned results,the immunofluorescence assay also displayed the expression of NBCe1 was decreased.Correlation analysis showed that NBCe1 expression levels were negatively correlated with DAI scores and IL1β level.Transepithelial electrical resistance of mucosal layer in DSS mice was smaller than that of the control.The variation of current after adding S0859 in DSS mice was decreased indicated the compromised function of NBCe1 transporter.The mucous layer thickness of DSS mice was significantly thinner(p=0.0052).The genetic expression of mucin2 in DSS group was increased,while Muc5 AC was decreased.The mucous secretion rate of the colonic mucosal tissue was significantly decreased after 20 min of S0859 stimulation,and the genetic expression of muc5 AC and CAIX was significantly increased.Conclusion: The expression of NBCe1 was down-regulated in colon tissues of IBD patients,colon cancer patients and DSS model mice.Moreover,the degree of intestinal inflammation is negatively correlated with the expression of NBCe1.In addition,NBCe1 influenced intestinal mucous secretion,which may affect the mucus barrier and participate in the development of inflammatory bowel disease.