Under Different Nutrient Conditions, The Intestinal Lymph Duct Ligation On Lung Injury And Inflammation

Background:Severe injury is often associated with intestinal ischemia/reperfusion (I/R) and that is the most common cause of ALI,MODS and SIRS.One factor thought to be important in the etiology is failure of the intestinal barrier resulting in bacterial translocation.Intestinal ischemia/reperfusion(I/R) causes local and remote injuries that are multifactorial and essentially inflammatory in nature.The release of injurious factors into the mesenteric lymph from the ischemic intestine has been shown to contribute to lung injury and systemic inflammation after severe injury.Objective:The purposes of this study are to test(1)the hypothesis that factors carried in the mesenteric lymph after the intestinal I/R contribute to the lung injury and systemic inflammatory reaction in different nutritional states and(2)whether special nutrients in enteral nutrition during intestinal I/R improves pulmonary function and attenuates the inflammation.Methods:Seventy-two Sprague Dawley rats underwent gastrostomy.The rats were fed with normal diet or received a continuous intragastric infusion of one of three diets:normal enteral nutrition,Gln-enriched with the Alanine-Glutamine dipeptide form,or immunonutrition rich ofω-3 PUFA,vitamins.The three formulas were isocaloric(1046kJ·kg^-1·d^-1) and isonitrogenous(1.8g N·kg^-1·d^-1).After receiving their respective diets for 7 days,rats were subjected to 60 minutes of intestinal ischemia,or ischemia plus mesenteric lymph duct ligation,or sham procedures(control).After 3 days of ischemia or sham,lymph nodes,lung,intestinal,liver,and blood were harvested.Pulmonary myeloperoxidase,NO,NOS levels,alveolar apoptosis were used to quantitate lung injury.Intestinal morphology,and DAO were measured. Ratios of lactulose/mannitol excretion in urine had been used to assess the extent of intestinal permeability.Serum levels of cytokines,endotoxin,ALT,AST,and D-lactate were quantified.Results:These results demonstrate a long-term deleterious effect of a non-lethal ischemia on intestinal barrier function and may be one explanation for many of the sequelae occurring after ischemia.In the different groups,lung injury,including the levels of MPO,NO,NOS,and the index of alveolar apoptosis,were partially prevented by mesenteric lymph duct ligation.Likewise,the intestinal I/R rats,but not the duct-ligated intestinal I/R rats,had a significant increase in the intestinal permeability,and lower mucosal thickness.The serum cytokine and endotoxin concentrations were also lower in lymph duct ligation groups,although not all were significant difference between lymph duct ligation and or not.The lung and intestinal injury were attenuated in the groups of glutamine and immunonutrition.Enteral glutamine or immunonutrition during intestinal I/R reduced the intestinal permeability and the serum levels of cytokines and endotoxin.Conclusions:Interruption of lymph flow from the gut into the bloodstream by lymph duct ligation prevents lung injury,system inflammation reaction,and gut barrier dysfunction.Enteral glutamine and immunonutrtition modified the gut inflammation, prevented lung injury,and attenuated the system inflammation reaction.