Relationship between plasma D(-)-lactate and intestinal damage after severe injuries in rats

AIM To explore the kinetic changes in plasma D(-)- lactate and lipopolyssccharide(LPS)levels,and investigate whether D(-)-lactate could be used as a marker of intestinal injury in rats following gut ischemia/ reperfusion,burn,and acute necrotizing pancreatitis (ANP). METHODS Three models were developed in rats:① gut ischemia/ reperfusion obtained by one hour of superior mesenteric artery occlusion followed by reperfusion;② severe burn injury created by 30% of total body surface area(TBSA)full-thickness scald burn;and ③ ANP induced by continuous inverse infusion of sodium taurocholate and trypsin into main pancreatic duct. Plasma levels of D(-)-lactate in systemic circulation and LPS in portal circulation were measured by enzymatic- spectrophotometric method and limulus amebocyte lysate (LAL)test kit,respectively.Tissue samples of intestine were taken for histological analysis. RESULTS One hour gut ischemia followed by reperfusion injuries resulted in a significant elevation in plasma D(-)- lactate and LPS levels,and there was a significant correlation between the plasma D(-)-lactate and LPS(r =0.719,P<0.05).The plasma concentrations of D(-)- lactate and LPS increased significantly at 6h postburn, and there was also a remarkable correlation between them (r = 0.877,P < 0.01).D(-)-lactate and LPS levels elevated significantly at 2h after ANP,with a similar significant correlation between the two levels(r = 0.798, P < 0.01 ).The desquamation of intestine villi and infiltration of inflammatory cells in the lamina propria were observed in all groups. CONCLUSION The changes of plasma D(-)-lactate levels in systemic blood paralleled with LPS levels in the portal vein blood.The measurement of plasma D(-)-lactate level may be a useful marker to assess the intestinal injury and to monitor an increase of intestinal permeability and endotoxemia following severe injuries in early stage.