Exacerbation of intestinal permeability in rats after a two-hit injury: burn and Enterococcus faecalis infection.
OBJECTIVE
To determine alterations in intestinal epithelial permeability to solutes in burn injured rats with and without Enterococcus faecalis infection and the role of neutrophils in the intestinal permeability changes.


METHODS
Prospective sham-controlled animal study.


METHODS
University research laboratory.


METHODS
Male Sprague-Dawley rats.


METHODS
Rats were subjected to 30% total body surface burn (B group), E. faecalis infection (EF group) induced via intra-abdominal implantation of bacterial pellet, or combination of burn injury and E. faecalis infection (B+EF group).


RESULTS
In vivo measurements of intestinal permeability were carried out after intraluminal injection of H lactulose and C mannitol in the ileum of sham, B, EF, and B+EF groups of rats, 1 and 2 days after injury. Lactulose permeability was increased in the injured rat groups (B, EF, B+EF) on day 1 postinjury compared with sham. The combined injury group (B+EF) had the highest level of lactulose permeability. Although a significant change in lactulose permeability from day 1 to day 2 postinjury could not be demonstrated in the B and EF groups, lactulose permeability in the B+EF group on day 2 postinjury markedly decreased from day 1 but was still significantly higher than that in the sham group. Mannitol permeability was increased in all injured rat groups on day 1 postinjury; on day 2 it remained elevated post-B, decreased post-EF, and further increased after B+EF. Ex vivo measurements of lactulose movements across intestinal epithelial monolayers (IEC-18) were carried out in the presence of blood neutrophils from sham, B, EF, or B+EF rats. We also measured ex vivo transepithelial migration of neutrophils from sham, B, EF, or B+EF rat groups. Neither the transepithelial lactulose movement in the presence of neutrophils from, nor neutrophil migration in, the B or EF rats was significantly different from sham. However, a significant increase in transepithelial lactulose movement and neutrophil migration occurred in the B+EF group. Immunoblot analyses and in situ histochemical localizations of intestinal tight junction proteins, occludin and claudin-3, showed decreases in the distribution of occludin but not claudin-3 in the B, EF, and B+EF groups.


CONCLUSIONS
Alterations in intestinal solute permeability and disruption of tight junction integrity after a two-hit injury with burn and E. faecalis infection, but not after individual injuries of burn or E. faecalis infection, are likely associated with heightened neutrophil flux across the intestinal epithelium.
Samonte
Victoria A
VA
Burn and Shock Trauma Institute, Loyola University, Medical Center, Maywood, IL, USA.
Goto
Masakatsu
M
Ravindranath
Thyyar M
TM
Fazal
Nadeem
N
Holloway
Vallie M
VM
Goyal
Amit
A
Gamelli
Richard L
RL
Sayeed
Mohammed M
MM
D000818:Animals; D018988:Bacterial Translocation / Q000502:physiology; D002056:Burns / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D002199:Capillary Permeability / Q000502:physiology; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D002634:Chemotaxis, Leukocyte; D062465:Claudin-3; D004195:Disease Models, Animal; D013293:Enterococcus faecalis / Q000502:physiology; D016908:Gram-Positive Bacterial Infections / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D007082:Ileum / Q000378:metabolism / Q000503:physiopathology; D015151:Immunoblotting; D007150:Immunohistochemistry; D007267:Injections; D007413:Intestinal Mucosa / Q000382:microbiology / Q000503:physiopathology; D007792:Lactulose / Q000493:pharmacokinetics; D008297:Male; D008353:Mannitol / Q000493:pharmacokinetics; D008565:Membrane Proteins / Q000032:analysis; D020556:Neutrophil Infiltration; D062793:Occludin; D051381:Rats; D017207:Rats, Sprague-Dawley; D019108:Tight Junctions / Q000737:chemistry; D013997:Time Factors
D002250:Carbon Radioisotopes; D062465:Claudin-3; C568124:Cldn3 protein, rat; D008565:Membrane Proteins; D062793:Occludin; C568987:Ocln protein, rat; D008353:Mannitol; D007792:Lactulose