Increased intestinal permeability in rats subjected to traumatic frontal lobe percussion brain injury.
BACKGROUND
Dysfunction of the gastrointestinal tract is a common occurrence after traumatic brain injury (TBI). We hypothesized that increased intestinal permeability may result from a precisely controlled percussion injury to the exposed brains of anesthetized rats and that such an effect could be assessed in vitro using excised intestinal mucosae mounted in Ussing chambers.


METHODS
After craniotomy over the left medial prefrontal cortex on anesthetized rats, neurotrauma was produced using a pneumatically driven impactor on the exposed brain. Control rats were subjected to identical procedures but did not receive an impact. Muscle-stripped rat intestinal ileal and colonic segments were mounted in Ussing chambers within 30 minutes of death. Transepithelial electrical resistance (TEER) and the apparent permeability coefficient (Papp) of [C]-mannitol were recorded from intestinal tissue for 120 minutes. Histopathologic analysis was also performed to determine any gross morphologic changes in the intestine.


RESULTS
Ileal and colonic mucosae showed no differences in TEER in ileum or colon of TBI rats compared with controls. The Papp of mannitol was significantly increased in ilea from rats previously exposed to TBI compared with controls. Histologic analysis showed gross changes to 50% of the ileal but not the colonic sections from TBI rats.


CONCLUSIONS
TBI results in significantly reduced ileal barrier function, most likely mediated by open tight junctions. For patients with acute head injury, this may have implications for subsequent oral absorption of nutrients. Systemic delivery of luminal endotoxins may contribute to multiple organ failure.
Feighery
Linda
L
UCD Conway Institute and School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland.
Smyth
Aoife
A
Keely
Simon
S
Baird
Alan W
AW
O'Connor
William T
WT
Callanan
John J
JJ
Brayden
David J
DJ
D000818:Animals; D001921:Brain / Q000473:pathology; D001930:Brain Injuries / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D003106:Colon / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005625:Frontal Lobe / Q000293:injuries; D007082:Ileum / Q000378:metabolism / Q000473:pathology; D007408:Intestinal Absorption / Q000502:physiology*; D007413:Intestinal Mucosa / Q000378:metabolism; D010539:Permeability; D051381:Rats