Correlation between acute gastrointestinal injury severity and intestinal microenvironment in rabbits with severe multiple trauma / 中华创伤杂志

ABSTRACT

Objective To investigate the correlation between acute gastrointestinal injury severity and intestinal microenvironment in rabbits with severe multiple trauma.Methods A total of 60 New Zealand white rabbits were enrolled and randomly assigned into the experimental group (48 rabbits) and control group (12 rabbits).In experimental group,the models of traffic-induced injuries were successful made by using self-made small gravity traction colliders.There were nine rabbits with craniocerebral injury combined with damage of liver and spleen,three with four extremity fractures combined with damage of liver and spleen,12 with rib fractures combined with damage of lungs and pleural effusion,11 with epidural hematoma,contusion and laceration of brain as well as fractures of four extremities and pelvis,and nine with multiple fractures.The injuries had met the criteria of multiple severe traumas according to the injury severity score (ISS).The control group had similar condition with experimental group except for participation in injury model.The parameters at time points of 6,12,24 and 48 h after injury were observed.The parameters were:(1)Enzyme linked immunosorbent assay (ELISA) and high pressure liquid chromatography (HPLC) were used to detect the levels of diamine oxidase (DAO) and the ratio of lactulose to mannitol in urine in order to evaluate the permeability of intestinal mucosal barrier.(2) The small intestinal propulsive rate was detected by carbon pushing mcthod.The interstitial cells of Cajal in the snall intestine wall were observed by transmission electron microscopy.The expression of C-kit was detected by Western blot.By these means,the dynamic function of intestinal mucosal barrier was evaluated.(3) The damage degree of intestinal nucosal barrier was evaluated by pathological observation and Chiu score in the end of small intestine and colon.(4)The intestinal bacterial translocation was evaluated by intestinal microflora culture,mesenteric lymph nodes checking as well as translocation examination of liver and spleen.Results (1) The level of DAO plasma and urine lactulose/mannitol ratio at 6 h after injury increased to varied degrees,and reached the peak during 12-24 h,the correlation analysis of which showed that plasma DAO levels were positively correlated with AGI grade at 6,12 and 24 h (r =0.486 3,0.493 3,0.477 6,P ＜ 0.05).The ratio of urinary lactulose/ mannitol excretion was only positively correlated with AGI grade at 6 and 12 h (r =0.478 5,0.497 2,P ＜ 0.05).(2) The gastrointestinal transmission rate in the experimental group was (48.2 ± 5.2) ％,and that of the control group was (60.3 ± 3.0) ％.The gastrointestinal transmission rate of model group rabbits was significantly longer than that of control group (P ＜ 0.05).(3) The interstitial cells of Cajal decreased dramatically during 12-24 h after the injury,and the expression level of C-kit protein decreased consistently with the increase of AGI grade.(4) The intestinal and colonic mucosa tissues of the experimental group showed obvious necrosis at 12-24 h after injury,and the Chiu score increased gradually with the increase of AGI grade under light microscope.(5) The Enterobacter and Enterococcus in the experimental group increased significantly compared with that in the control group.But the numbers of Bifidobacterium,Lactobacillus,Lactobacillus,Bacteroides as well as the ratio of Bifidobacterium to Enterobacteriaceae significantly decreased(P ＜0.05).(6)The organ bacterial translocation rates were 24％,42％ and 62％ after injury in experimental group (P ＜0.05).Conclusions Acute gastrointestinal injury may occur early after severe multiple trauma,and the injury severity is closely related to the change of intestinal barrier function and bacterial translocation.Early attention and active correction of the change of intestinal microenvironment are of great importance for treatment of multiple trauma.