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

To investigate the mechanism underlying intestinal barrier function damage after severe trauma and the therapeutic effect of glutamine.

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.

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.

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.