Objective   To investigate the intestinal pathophysiological mechanism of bacterial translocation and    endotoxemia in rabbits with acute spinal cord injury  (SCI).    Methods   Paraplegia was induced by injuring the spinal cord of 30 rabbits by the method of Fehlings. Twelve rabbits were used for recording the changes of   gastrointestinal (GI) electrophysiology and colon pressure. The left 18 rabbits were experimental group and were killed in 24

48 and 72 h after injury. The other 6 rabbits served as normal group. Under aseptic condition

samples of blood and mesenteric lymph node were collected for bacterial cultures and endotoxin detection. The small intestines were observed by light and electron microscopy. The colons were inspected by light microscopy.    Results   After SCI

the electrophysiology of the GI tract was changed especially at the middle and distal colon. The peristalsis of the middle and distal colon was reduced and sometimes even disappeared. In the early stage

the main pathology was hyperemia of blood vessel and infiltration of inflammatory cells. The interepithelial tight junctions became wider and the columnar epithelium was disintegrated. All of the pathological changes may lead to the destruction of the intestinal barrier. The endotoxin level were increased since 24 h after SCI and had statistically significant difference compared with that at 72 h (P0.05). The positive rates in blood and mesenteric lymph nodes at 24

48 and 72 h were very high

but there was no significant difference among them (P0.05).    Conclusion   After SCI

the middle and distal colon dysfunction induces constipation

bacterial overgrowth

and blood flow congestion. These factors may accelerate the destruction of the intestinal barrier and lead to bacterial translocation and endotoxemia.