[Effect of oxygen free radicals on bacterial translocation in rats with traumatic brain injury]

To investigate the effect of oxygen free radicals on intestinal mucosal barrier in traumatic brain injury rats.

A total of 64 health male Wistar rats were divided randomly into two groups: traumatic brain injury (TBI) (n=32); Control group with sham operation (n=32). Each group was divided into four subgroups at 6, 12, 24 and 48 h post-operation (n=8). The levels of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) were measured in intestinal mucosa, mesenteric lymph nodes, liver, spleen, pancreas, lung and kidney tissue. The marked bacilli were counted under a fluorescent microscope.

The positive rates of bacterial translocation in TBI group were obviously higher than those of control group (6 h: 8.3% vs. 2.1%, 12 h: 25.0% vs. 2.1%, 24 h: 27.1% vs. 2.1%, 48 h: 12.5% vs. 0.0% , P < 0.05). The levels of MDA in TBI group were obviously higher than those of control group (6 h: 4.9 +/- 0.7 vs. 2.6 +/- 0.3, 12 h: 6.1 +/- 0.8 vs. 2.8 +/- 0.5, 24 h: 5.9 +/- 0.4 vs. 2.6 +/- 0.3, 48 h: 5.3 +/- 0.5 vs. 2.7 +/- 0.4 (nmol/mg pro), P < 0.05), and GSH (6 h: 287 +/- 36 vs. 408 +/- 253; 12 h: 192 +/- 25 vs. 421 +/- 46; 24 h: 160 +/- 48 vs. 432 +/- 35; 48 h: 241 +/- 31 vs. 394 +/- 51 (mg/g pro) P < 0.05). SOD (6 h: 19.5 +/- 3.3 vs. 21.1 +/- 1.9; 12 h: 11.8 +/- 2.6 vs. 20.7 +/- 5.3; 24 h: 13.3 +/- 3.3 vs. 20 +/- 3.3; 48 h: 15.1 +/- 1.5 vs. 21.2 +/- 3.2 (U/mg pro). P < 0.05) were lower than the control group at the same time point.

Bacterial translocation occurs obviously in TBI rats. It indicates that oxygen free radicals play important roles in stress-related changes of intestinal mucosal barrier in early stage of traumatic brain injury.