The influences of different nutritional formulas and routes on the intestinal barrier in rats with gut ischemia/reperfusion injury

Objectives: In this study,we evaluated the influence of different nutritional support routes and nutrients on the intestinal barrier function and bacterial translocation in rats with gut I/R injury. Methods: Sixty male Sprague Dawley rats were made ischemic by clamping the superior mesenteric artery for 30 minutes and were divided randomly into four groups of fifteen animals each,i.e.standard parenteral nutrition (PN),gln enriched TPN (G PN),common enteral nutrition (EN),and enteral immunonutrient (IEN) groups. All the rats received isocaloric nutrition support for seven days.Rats were killed after 7 days'nutrition support.Spleen,liver,mesenteric lymph nodes (MLN),and blood samples were collected for bacterial culture. Endotoxin levels in plasma were also measured.The permeability of intestine mucosa was assayed by D lactate level in plasma.The small intestine was removed for studies.Mucosal thickness,villous height,crypt depth and villous surface area were determined.The gut immune barrier function was evaluated by the immunohistochemical staining method. Results: Atrophy occurred in small intestinal mucosa in PN group.The mucosal thickness,villous height,crypt depth and villous surface area were decreased significantly in PN group compared with other groups ( P 0.05).The morphometric changes in EN group were better than that in G PN group ( P 0.01). The incidence of intestinal bacterial translocation to spleen,liver,MLN,and blood was significantly higher in PN group(100.0%) than those in other groups(G PN group 60.0%;EN group 33.3% and IEN group 20.0%) ( P 0.05).There was no significant difference between EN and IEN groups about bacterial translocation positive rate( P =0.682).The endotoxin levels were the highest in the PN group (12.00±0.99pg/ml).Significantly higher values of D lactate were also seen in PN group. CD4 +,CD4 +/CD8 + and IgA containing B cells in G PN group were higher than those in PN group ( P 0.01). Conclusions: The results suggest that TPN alone could impair gut barrier function and therefore facilitated bacterial translocation.Immunonutrition can significantly benefit gut immune barrier function.