[Dendritic cells: another possible carrier for gastrointestinal bacterial translocation]

To observe the immigration and morphological changes of peripheral dendritic cells (DCs) after hemorrhagic shock and to understand the role of DCs in bacterial translocation (BT) from the gastrointestinal tract.

Forty-eight Wistar rats were randomly divided into sham-operated group (n=8) which did not receive phlebotomy and hemorrhagic shock group (n=40) in which hemorrhagic shock was induced with Wigger's method, with the carotid pressure manipulated at 5.3 kPa for 1 h before resuscitation by transfusion of the blood from previous phlebotomy along with infusion of Ringer's solution of the same volume. Using sterile technique, the mesenteric lymph nodes (MLNs) were sampled at 3, 6, 12, 24 and 48 h respectively (n=8) following the resuscitation, and immunohistochemical study and bacterial culture were conducted.

In the sham-operated group, bacterial culture yielded only l positive results, while in the hemorrhagic shock group all animals were shown positive for bacteria. The number of DCs and amount of the bacteria in the MLNs increased significantly after hemorrhagic shock, both reaching the maximum at 12 h in a highly correlative manner (r=0.89). Morphologically, DCs in the hemorrhagic shock group with abundant dendritic processes differed from those of the sham-operated rats, the latter with scarce changes during the experiment.

Hemorrhagic shock results in morphological and functional transformations of gastrointestinal DCs, the number of which is in positive correlation with the amount of bacteria in the MLN, indicating that DCs, besides the macrophages, are also important bacteria carriers during the generation of BT.