Mesenteric microcirculatory dysfunctions and translocation of indigenous bacteria in a rat model of strangulated small bowel obstruction.
OBJECTIVE
Bacterial translocation has been shown to occur in critically ill patients after extensive trauma, shock, sepsis, or thermal injury. The present study investigates mesenteric microcirculatory dysfunctions, the bacterial translocation phenomenon, and hemodynamic/metabolic disturbances in a rat model of intestinal obstruction and ischemia.


METHODS
Anesthetized (pentobarbital 50 mg/kg, i.p.) male Wistar rats (250-350 g) were submitted to intestinal obstruction or laparotomy without intestinal obstruction (Sham) and were evaluated 24 hours later. Bacterial translocation was assessed by bacterial culture of the mesenteric lymph nodes (MLN), liver, spleen, and blood. Leukocyte-endothelial interactions in the mesenteric microcirculation were assessed by intravital microscopy, and P-selectin and intercellular adhesion molecule (ICAM)-1 expressions were quantified by immunohistochemistry. Hematocrit, blood gases, lactate, glucose, white blood cells, serum urea, creatinine, bilirubin, and hepatic enzymes were measured.


RESULTS
About 86% of intestinal obstruction rats presented positive cultures for E. coli in samples of the mesenteric lymph nodes, liver, and spleen, and 57% had positive hemocultures. In comparison to the Sham rats, intestinal obstruction induced neutrophilia and increased the number of rolling (approximately 2-fold), adherent (approximately 5-fold), and migrated leukocytes (approximately 11-fold); this increase was accompanied by an increased expression of P-selectin (approximately 2-fold) and intercellular adhesion molecule-1 (approximately 2-fold) in the mesenteric microcirculation. Intestinal obstruction rats exhibited decreased PaCO2, alkalosis, hyperlactatemia, and hyperglycemia, and increased blood potassium, hepatic enzyme activity, serum urea, creatinine, and bilirubin. A high mortality rate was observed after intestinal obstruction (83% at 72 h vs. 0% in Sham rats).


CONCLUSIONS
Intestinal obstruction and ischemia in rats is a relevant model for the in vivo study of mesenteric microcirculatory dysfunction and the occurrence of bacterial translocation. This model parallels the events implicated in multiple organ dysfunction (MOD) and death.
Zanoni
Fernando Luiz
FL
Heart Institute (InCor), LIM 11, University of São Paulo Medical School, São Paulo/SP, Brazil. zanoni@usp.br
Benabou
Simon
S
Greco
Karin Vicente
KV
Moreno
Ana Carolina Ramos
AC
Cruz
José Walber Miranda Costa
JW
Filgueira
Fernando Paranaiba
FP
Martinez
Marina Baquerizo
MB
Figueiredo
Luiz Francisco Poli de
LF
Silva
Maurício Rocha e
MR
Sannomiya
Paulina
P
D000818:Animals; D018988:Bacterial Translocation / Q000502:physiology*; D015415:Biomarkers / Q000097:blood; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000502:physiology*; D007150:Immunohistochemistry; D007415:Intestinal Obstruction / Q000097:blood / Q000382:microbiology / Q000503:physiopathology*; D007421:Intestine, Small / Q000098:blood supply* / Q000382:microbiology / Q000503:physiopathology; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D009102:Multiple Organ Failure / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar
D015415:Biomarkers