Use of an extracorporeal circuit to evaluate effects of intraluminal distention and decompression on the equine jejunum.
OBJECTIVE
To use an extracorporeal circuit to evaluate effects of intraluminal distention on the jejunum of healthy horses.


METHODS
2 jejunal segments from each of 5 horses.


METHODS
Jejunal segments were harvested and maintained in an extracorporeal circuit. One segment was subjected to distention (intraluminal pressure, 25 cm H2O) followed by decompression, and 1 segment was maintained without distention. The influence of distention-decompression on vascular resistance was calculated. Mucosal permeability was evaluated by measuring the clearance of albumin from blood to lumen. After distention and decompression, tissue specimens were collected for histomorphologic evaluation. In addition, the contractile response of the circular smooth muscle layer was determined following incubation with 3 prokinetic agents.


RESULTS
Intestinal vascular resistance increased during intraluminal distention and returned to baseline values after decompression. Albumin clearance rate increased after distention, compared with baseline and control values. Histologic examination of the distended segments revealed grade-1 and -2 lesions of the mucosal villus. Edema and hemorrhage were evident in the submucosa and muscular layers. Mesothelial cell loss, edema, and hemorrhage were also evident in the serosa. Mucosal surface area and villus tip height decreased and submucosal volume increased in the distended tissue. Compared with responses in control specimens, distention decreased the contractile response induced by cisapride, erythromycin, and metoclopramide.


CONCLUSIONS
Intraluminal distention of the jejunum followed by decompression increased mucosal permeability and injury and decreased responses to prokinetic agents. Horses with intraluminal intestinal distention may have a decreased response to prokinetic agents.
Nieto
Jorge E
JE
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis 95616, USA.
Van Hoogmoed
Linda M
LM
Spier
Sharon J
SJ
Vatistas
Nicholas J
NJ
Snyder
Jack R
JR
Timmerman
Brenna L
BL
D000418:Albumins / Q000493:pharmacokinetics; D000818:Animals; D020117:Cisapride / Q000494:pharmacology; D004917:Erythromycin / Q000494:pharmacology; D005112:Extracorporeal Circulation / Q000662:veterinary*; D006736:Horses / Q000502:physiology*; D007413:Intestinal Mucosa / Q000502:physiology; D007583:Jejunum / Q000187:drug effects / Q000502:physiology*; D008787:Metoclopramide / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D014655:Vascular Resistance
D000418:Albumins; D004917:Erythromycin; D008787:Metoclopramide; D020117:Cisapride