Effect And Mechanism Of Early Enteral Nutrition On Intestinal Immune Barrier In Rats With Severe Acute Pancreatitis

Objective: Measuring the serum amylase(AMY),glucose(GLU), endotoxin level, the MAdcAM-1(mucosal addressin celladhesion molecule-1), CD4+, CD8+level in terminal ileum and peyerspatches, the intestinal TLR4expression, and bacterial culture of portalvein, pancreas, lung, mesenteric glands of Sodium taurocholate inducedsevere acute pancreatitis rats treated with Early enteral nutrition, toinvesgate the role of early enteral nutrition on intestinal immune barrier inrats with severe acute pancreatitis. Method:60healthy adult male SDrats weight272±25g, were randomly divided into three groups. Eachgroup has20rats. Sham operation group (SO group): laparotomy onlygently flip the duodenum and pancreas, then close the abdomen, nofurther treatment was given. Multi-point injected with1ml3.8%sodiumtaurocholate under capsule of pancreas was used to build severe acutepancreatitis rats, then parenteral nutrition and enteral nutrition was givenseparately. Total parenteral nutrition group(TPN):12hours after themodel was bulit, insert a tube in external jugular vein to transfuseparenteral nutrient solution. Early enteral nutrition group(EEN):12hoursafter the model was bulit, transfuse enteral nutrient solution throughartificial jejunal fistula.1day after the model was bulit, collect venous blood from jugular vein, measure the AMY and GLU level.5days afternutrient solution was given, calculate the mortality rate of rats, then killall the rats and collect the tissue we need. Jejunum, ileum, colon tissuestained with HE were observed to study intestinal mucosa morphology.Immunohistochemistry was performed on terminal ileum and peyerspatches to measure MAdCAM-1, CD4+, CD8+content. Use Westen blotto measure intestinal TLR4expression. And measure the venous bloodendotoxin content. Portal vein blood, pancreas, lung tissue and mesentericglands was collected to have bacterial culture, measure the incidence ofbacterial translocation. Result:(1)5days survival rate of each group: SOgroup was100%, TPN group was50%, EEN group was25%. There weresignificant differences between SO group and the other twogroups(P<0.01). There was no significant difference between EEN groupand TPN group(P>0.05).(2)Changes of AMY: AMY of TPN and EENgroup were significantly increased after24hours, which were bothsignificant different from SO group(P<0.01).24hours after the modelwas bulit, AMY of EEN group was significantly lower than TPNgroup(P<0.01).(3) Changes of GLU: GLU of TPN and EEN group weresignificantly increased after24hours, which were both significantdifferent from SO group(P<0.01). There was no significant differencebetween EEN group and TPN group(P=0.0847).(4) Pancreas histologyscore:5days after the model was built, pancreas histology score of TPN and EEN group were significantly increased compared with SOgroup(P<0.01). Pancreas histology score of TPN group wassignificantly higher than EEN group(P<0.01).(5)endotoxin content ofeach group:5days after the model was bulit, endotoxin content of TPNand EEN group were significantly increased compared with SO group,indicating that both group have injured gut barrier. Endotoxin content ofEEN group was significantly lower than TPN group(P<0.05), indicatingthat EEN can lower the permeability of gut barrier, showing a protectiveeffect of gut barrier.(6) Incidence of bacterial translocation:Gram-negative bacteria constituted the majority of bacteria, E.coliaccounted for85.7%(12/14). Incidence of bacterial translocation in EENgroup was significantly lower than TPN group(P<0.01), in both EEN andTPN group incidence of bacterial translocation were significantly higherthan SO group(P<0.01).(7)MAdCAM-1, CD4+, CD8+content interminal ileum and peyers patches by immunohistochemistry: CD4+、CD8+、MadcAM-1content in EEN and TPN group were significantlylower than SO group(P<0.05), and TPN group was significantly lowerthan EEN group(P<0.05).(8)Ileum morphology: After5days, mucosalthickness and villus height of TPN group were significantly decreasedcompared with EEN group(P<0.01).(9)TLR4expression by Westen blot:TLR4expression in EEN and TPN group were significantly increasedcompared with SO group(P<0.05). TLR4expression in EEN group was significantly decreased compared with TPN group(P<0.05). Conclusion:(1) Multi-point injected with1ml3.8%sodium taurocholate undercapsule of pancreas is a reproducible, inexpensive, simple and convenientway to build a severe acute pancreatitis rats model. The SAP rats has aProgressive development of disease, similar to the natural course ofhuman SAP, the mortality of the rats is stable, so it’s suitable for study ofEEN therapy of SAP.(2)EEN does not aggravate SAP, it’s a safe andfeasible treatment of SAP. EEN has a remarkable effect on the protectionof gut barrier, it’s beneficial for the mechanical, chemical, biological,immunization function of intestinal barrier. Especially, EEN increasesexpression of MAdCAM-1, CD4+, CD8+, enhances the immune barrierfunction, reduces bacterial translocation, and reduces the risk of local andsystemic infection, improves5days survival of SD rats.(3)We speculatethat TLR4plays a important role in SAP associated intestinal injury,through the combination of its specific ligand LPS, expression level ofTLR4is positive correlated with inflammation condition.