[Impact of glutamine and ω-3 polyunsaturated fatty acids on intestinal permeability and lung cell apoptosis during intestinal ischemia-reperfusion injury in a rat model].

OBJECTIVE

To investigate the impact of intestinal lymphatic vessels ligation and different enteral nutrition support during ischemia/reperfusion on intestinal permeability, systemic inflammatory response and pulmonary dysfunction in a rat model.

METHODS

Seventy-two Sprague-Dawley male rats were randomized into normal diet group, regular enteral nutrition group, glutamine-enriched group, 0-3 polyunsaturated fatty acids (wo-3PUFA) group, and sham control after gastrostomy. All the enteral nutrition group were isocaloric (1046 kJ kg-' d-1) and isonitrogenous (1.8 g N kg-' d-'). After enteral nutrition for 7 days, the rats were subjected to intestinal ischemia for 60 min, or ischemia plus mesenteric lymph duct ligation except for the sham group followed by 3 days of nutrition (72 h). Intestinal permeability (lactose/mannitol ratio in the urine, L/M) was determined on the 5th, 7th and 9th day after gastrostomy. The levels of serum diamine oxidase, endotoxin, cytokines, ALT and AST were detected at the 11th day after gastrostomy. Mucosal thickness was measured using small intestine and villusheight. Myeloperoxidase (MPO), nitric oxide (NO), NO synthase, and apoptotic index were detected in lung tissue.

RESULTS

Ischemia for 60 min could cause intestinal injury. Intestinal permeability(L/M)was increased significantly in every group on the first day after ischemia (P<0.05). However, L/M decreased significantly 3 days after ischemia (P<0.05). The groups with Glu and o-3PUFA-enriched nutrition almost restored to normal level (P>0.05). The level of L/M in lymphatic ligation group was significantly lower than non-ligation group (P<0.05). The levels of endotoxin and cytokine were reduced, mucosal thickness and villous height were significantly higher (P<0.05) in the groups of Glu and o-3PUFA-enriched nutrition compared with enteral nutrition and normal diet groups during intestinal ischemia-reperfusion injury. MPO, NO, NOS and the apoptosis index of lung tissue decreased in the groups of Glu and o-3PUFA-enriched as well as after lymph duct ligation (P<0.05).

CONCLUSIONS

The distant tissue-lung damage and systemic inflammation caused by intestinal ischemia-reperfusion injury may be related to some factors in the intestinal lymph. Blocking the gut-lymph pathway and/or adding Glu and o-3PUFA in enteral nutrition may reduce intestinal permeability and endotoxin, increase mucosal thickness, attenuate the systemic inflammatory reaction, and prevent lung injury