Complement activation mediates intestinal injury after resuscitation from hemorrhagic shock.
BACKGROUND
Endothelial cell injury after hemorrhage and resuscitation (HEM/RES) might contribute to intestinal hypoperfusion and mucosal ischemia. Our recent work suggests that the injury might be the result of complement activation. We hypothesized that HEM/RES causes complement-mediated endothelial cell dysfunction in the small intestine.


METHODS
Male Sprague-Dawley rats (195-230 g) were anesthetized and HEM to 50% of baseline mean arterial pressure for 60 minutes. Just before RES, animals received either soluble complement receptor-1 (sCR1, 15 mg/kg) to inhibit complement activation or saline vehicle. Resuscitation was with shed blood and an equal volume of saline. Two hours after RES, the small bowel was harvested to evaluate intestinal nitric oxide synthase activity (NOS), neutrophil influx, histology, and oxidant injury.


RESULTS
HEM/RES induced tissue injury, increased neutrophil influx, and reduced NOS activity by 50% (vs. SHAM), all of which were completely prevented by sCR1 administration. There were no observed differences in oxidant injury between the groups.


CONCLUSIONS
Histologic tissue injury, increased neutrophil influx, and impaired NOS activity after HEM/RES were all prevented by complement inhibition. Direct oxidant injury did not seem to be a major contributor to these alterations. Complement inhibition after HEM might ameliorate reperfusion injury in the small intestine by protecting the endothelial cell, reducing neutrophil influx and preserving NOS function.
Department of Surgery, University of Louisville School of Medicine, Kentucky 40292, USA. daspai01@athena.louisville.edu
D A
DA
Spain
T M
TM
Fruchterman
P J
PJ
Matheson
M A
MA
Wilson
A W
AW
Martin
R N
RN
Garrison
D000818:Animals; D003167:Complement Activation / Q000276:immunology*; D015237:Dinoprost / Q000032:analysis; D004195:Disease Models, Animal; D007413:Intestinal Mucosa / Q000098:blood supply*; D007511:Ischemia / Q000201:enzymology / Q000209:etiology* / Q000276:immunology* / Q000473:pathology; D016014:Linear Models; D008297:Male; D018375:Neutrophil Activation / Q000276:immunology; D019001:Nitric Oxide Synthase / Q000032:analysis; D009195:Peroxidase / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012151:Resuscitation / Q000009:adverse effects* / Q000379:methods; D012771:Shock, Hemorrhagic / Q000150:complications* / Q000628:therapy
D015237:Dinoprost; D009195:Peroxidase; D019001:Nitric Oxide Synthase