Preventive effect of glutamine on intestinal barrier dysfunction induced by severe trauma

AIM: To investigate the mechanism underlying intestinal barrier function damage after severe trauma and the therapeutic effect of glutamine. METHODS: Burned patients, and animal models of severe trauma replicated by hemorrhagic shock combined with endotoxin infusion and burn injury, were included in a serial experiment. Effects of oral glutamine on intestinal barrier function were observed in scalded rats. Parameters measured in these experiments were as follows: plasma levels of diamine oxidase (DAO), tumor necrosis factor (TNFalpha), endotoxin (LPS), and lactate as well as D-lactate by biochemical methods, lactose/mannitol (L/M) ratio in urine by SP-3400, and pathological examination of intestinal mucosa under light microscopy. RESULTS: Plasma DAO activity was significantly increased after injury. There was a negative correlation between plasma DAO and intestinal mucosal DAO or pHi (r=-0.93, plasma 0.80+/-0.93,2.83+/-1.71, 1.14+/-0.64,2.36+/-2.06 and 2.49+/-1.67 vs intestinal 0.52+/-0.12,0.34+/-0.03,0.45+/-0.18,0.37+/-0.26 and 0.41+/-0.07 r=-0.533, plasma 0.87+/-0.75, 1.89+/-1.13,1.21+/-0.23,3.03+/-2.61 and 4.70+/-1.22 vs pHi 7.03+/-0.05,7.05+/-0.06,7.14+/-0.096, 7.20+/-0.08 and 7.05+/-0.07 P<0.01-0.05). Positive correlations were found between DAO activity and plasma TNFalpha, LPS, lactate, L/M and D-lactate (r=0.817, 0.842, 0.872, and 0.951 plasma DAO 0.87+/-0.75,1.89+/-1.13,1.21+/-0.23,3.03+/-2.61 and 4.70+/-1.22 vs TNF 0.08+/-0.02,0.03+/-0.25, 0.17+/-0.09,0.34+/-0.15 and 0.33+/-0.18 vs LPS 0.14+/-0.03,0.16+/-0.04,0.21+/-0.02,0.18+/-0.16 and 0.37+/-0.10 vs lactate 9.03+/-2.19,18.30+/-2.56, 9.81+/-2.83,12.01+/-6.83,12.01+/-6.84 and 43.61+/-11.27 vs L/M 0.03+/-0.01,0.41+/-0.27,0.62+/-0.20, 1.70+/-0.60 r=0.774, plasma DAO 1.25+/-0.41 2.17+/-0.71 2.29+/-0.87 1.23+/-0.55 and 1.11+/-0.47 vs D-lactate 8.37+/-2.48,18.25+/-6.18, 13.96+/-4.94,8.93+/-3.00 and 12.39+/-4.94 all P<0.01), respectively. Damage of intestinal mucosa was found by pathological examination. Intestinal barrier function was improved to a certain extent by oral glutamine in scalded rats. CONCLUSION: Intestinal barrier function was damaged in the early stage after trauma. Plasma DAO activity, D-lactate content, intestinal pHi and urine L/M may be sensitive markers of intestinal mechanical injury, and glutamine may protect against intestinal barrier dysfunction after severe trauma.