| Objective:To observe the changes of the barrier function of intestine before and after abdominal surgery,to investigate the injury mechanism of intestinal mucosal barrier under stress of surgical trauma,study the effect of early enteral nutrition on gut barrier protection.Methods:This study was divided into two parts,clinical observation and animal testing.We selected patients with large and moderate abdominal surgery,collect peripheral blood before operation and the 1st day,4th day and 7th day post-operation.Evaluated the changes of diamine oxidase(DAO),malondialdehyde(MDA) and glutamine(Gln) in serum at different time points.In animal study,three groups of animal models were established:rat colon resection under enteral nutrition,colon resection under parenteral nutrition,and the normal control group.Animals with surgery were sacrificed at different time points. Mesenteric lymph nodes were taken under sterile conditions to determine the situation of intestinal bacterial translocation.Ileum and colon samples were collected, and mucosal thickness,villous height,crypt depth,villous surface were assessed by pathology examination.Immunohistochemical method was used to detect the changes of IgA~+ cells in the intestinal lamina propria.To compare the intestinal mucosal barrier function between rats with different nutritional support under traumatic stress of operation.Results:1.DAO in the post-operation plasma was significantly higher than that of preoperation(3.15±0.482 vs 1.43±0.473).From day 1st,4th to day 7th,a gradual decline was observed(2.31±0.485 vs 1.77±0.461),but still significantly higher than that of preoperation(P＜0.001).2.MDA in the post-operation plasma was significantly higher than that of preoperation(2.15±0.422 vs1.11±0.343).From day 1st,4th to day 7th,a gradual decline was observed(1.58±0.333 vs 1.33±0.328),but still significantly higher than that in the preoperation(P＜0.05). 3.Gln in the post-operation plasma was significantly lower than that of preoperation (1.15±0.425 vs 1.95±0.415).From day 1st,4th to day 7th,a gradual increase was observed(1.53±0.397 vs 1.75±0.399),but still lower than the preoperative level(P＜0.05).4.There are statistical diference among the values of DAO,MDA and Gln measured at different time point pre- and post-operation(P＜0.05).5.The DAO,MDA and Gln in the plasma of patients were analyzed for correlation, respectively.Gln were negatively correlated with DAO and MDA(P＜0.05),while DAO and MDA are positively correlated(P＜0.05).These differences have statistical significance..6.The intestinal thickness,villous height,crypt depth and villous surface area of rats were lower after operation compared to the control group,however,that in the early enteral nutrition group was significantly higher than that of the parenteral nutrition group(P＜0.05).The small intestinal mucosal thickness and villous surface of group EN2 was significantly higher than that of group EN1,The small intestinal mucosal thickness of PN2 was significantly higher than that of group PN1(P＜0.05).7.The thickness of colonic mucosa decreased after operation,and inflammatory cells increased compared with control group.However,the thickness of coloic mucosa in early enteral nutrition group was significantly higher than that of parenteral nutrition group(P＜0.05).8.Higher bacterial translocation rates in the mesenteric lymph nodes were observed after operation.Enteral nutrition significantly lower bacterial translocation compared to the parenteral nutrition(P＜0.05).9.The IgA~+ cells in the rat ileum,colon immunohistochemical lamina propria were lower after operation compared to preoperative,however,the amount of IgA~+ cells in the enteral nutrition group significantly higher than that of the parenteral nutrition group(P＜0.05).10.The amount of IgA~+ cells in the rat ileum,colon lamina propria were negatively correlated to the bacterial translocation rates in the mesenteric lymph nodes(r =-0.984,P＜0.05). 11.The amount of IgA~+ cells in the intestinal lamina propria were negatively correlated to the bacterial translocation rates of mesenteric lymph nodes(r=-0.955, P＜0.05).Conclusion:1.Traumatic stress from abdominal surgery led to intestinal barrier dysfunction in patients.The damage of intestinal barrier is closely related with the lack of Gln.2.After abdominal operation,intestinal barrier function in rats was significantly impaired.There was a negative correlation between numbers of IgA~+ cells in intestinal lamina propria and rates of bacterial translocation in mesenteric lymph nodes,which suggests the amount of sIgA in intestinal is closely related to bacterial translocation and the damage of intestinal barrier.The rate of intestinal bacterial translocation by Colonic mucosa damage caused is more prominent.3.There was a significant protective effect on gut barrier with early enteral nutrition. |
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