The Effect Of Obesity On The Formation Of Gastric Mucosa Associated Lymphoid Tissue (MALT) After Helicobacter Suis Infection

Objective To investigate the effect of high fat diet induced obesity on the formation of gastric mucosa associated lymphoid tissue(MALT)after Helicobacter suis(H.suis)infection and its possible mechanism by establishing obese mice model with H.Suis infection.Methods 1.Establishment of mice model with H.suis infection: A total of 40 female C57BL/6 mice were randomly divided into model group and control group.The mice in model group were given 0.5 m L pig gastric mucosal homogenates containing H.suis identified by PCR test,while the mice in control group were given the same amount of PBS.After 1 month and 3 months,half of each group were randomly sacrificed and their gastric mucosa were taken out to detect the H.suis colonization by PCR and the formation of lymphoid follicles by HE staining in the stomach.2.The effect of obesity on the formation of gastric mucosa associated lymphoid tissue(MALT)and the expression of related inflammatory factor after H.suis infection: After successful modeling,forty new female C57BL/6 mice were randomly divided into four groups(ten mice per group),which are named as normal control(NC)group,high fat diet(HFD)group,H.suis infection(HS)group and H.suis infection+ high fat diet(HS+HFD)group.The mice gastric mucosal homogenates(0.2 ml/mouse)with H.suis was given to the HS group and HS+HFD group.The mice of NC group and HS group continued to give an ordinary diet,while the mice of HFD group and HS+HFD group were given a high fat diet from the third week postinfection.At 24 weeks after different diet,all of the mice were sacrificed to collect their gastric tissues.The number and size of gastric lymphoid follicles were detected by HE staining and the m RNA expression levels of leptin and its receptor Ob-R,inflammatory cytokine IFN-?,chemokines CXCL13 ? CCL-2 in the gastric mucosa of mice were detected by real-time PCR.Results 1.H.suis existed in pig gastric mucosal homogenates used for gavage and could colonize in the stomach of mice after 1 months and 3 months postinfection.The formation of gastric lymphoid follicles was detected in the stomachs of mice after H.suisformation,and the size of follicles at 3 months postinfection increased significantly compared with that at 1 month postinfection.2.The number and size of gastric lymphoid follicles and the m RNA expression levels of leptin and its receptor Ob-R,IFN-?,CXCL13,CCL-2 in the gastric mucosa of HS+HFD group were significantly increased compared with HS group.Conclusion 1.The mice model with H.suis infection was established successfully;2.H.suis infection can induce the formation of lymphatic follicles in C57BL/6 mice.3.High fat diet induced obesity can promote the formation of gastric MALT after H.suis infection.That mechanism may be associated with the upregulation of the chain of leptin?IFN??CXCL13 expression.