Effects of intestinal mucosal blood flow and motility on intestinal mucosa

To investigate the role of intestinal mucosal blood flow (IMBF) and motility in the damage of intestinal mucosal barrier in rats with traumatic brain injury.

Sixty-four healthy male Wistar rats were divided randomly into two groups: traumatic brain injury (TBI) group (n=32), rats with traumatic brain injury; and control group (n=32), rats with sham-operation. Each group was divided into four subgroups (n=8) as 6, 12, 24 and 48 h after operation. Intestinal motility was measured by the propulsion ratio of a semi-solid colored marker (carbon-ink). IMBF was measured with the laser-Doppler technique. Endotoxin and D-xylose levels in plasma were measured to evaluate the change of intestinal mucosal barrier function following TBI.

The level of endotoxin was significantly higher in TBI group than in the control group at each time point (0.382±0.014 EU/mL vs 0.102±0.007 EU/mL, 0.466±0.018 EU/mL vs 0.114±0.021 EU/mL, 0.478±0.029 EU/mL vs 0.112±0.018 EU/mL and 0.412±0.036 EU/mL vs 0.108±0.011 EU/mL, P<0.05). D-xylose concentrations in plasma in TBI group were significantly higher than in the control group (6.68±2.37 mmol/L vs 3.66±1.07 mmol/L, 8.51±2.69 mmol /L vs 3.15±0.95 mmol/L, 11.68±3.24 mmol/L vs 3.78±1.12 mmol/L and 10.23±2.83 mmol/L vs 3.34±1.23 mmol/ L, P<0.05). The IMBF in TBI group was significantly lower than that in the control group (38.5±2.8 PU vs 45.6±4.6 PU, 25.2±3.1 PU vs 48.2±5.3 PU, 21.5±2.7 PU vs 44.9±2.8 PU, 29. 4±3.8 PU vs 46.7±3.2 PU) (P<0.05). Significant decelerations of intestinal propulsion ratio in TBI groups were found compared with the control group (0.48%±0.06% vs 0.62%±0.03%, 0.37%±0.05% vs 0.64%±0.01%, 0.39%±0.07% vs 0.63%±0.05% and 0.46%±0.03% vs 0.65%±0.02%) (P<0.05).

The intestinal mucosal permeability is increased obviously in TBI rats. Decrease of intestinal motility and IMBF occur early in TBI, both are important pathogenic factors for stress-related damage of the intestinal mucosal barrier in TBI.