Assessment of intestinal integrity after ischemic preservation by luminal and vascular perfusion in vitro.

Background: In the present study a technique for isolated perfusion of rat intestines in vitro should be tested as an evaluative tool in the assessment of intestinal alterations related to ischemia and reoxygenation.

Methods: Segments of upper jejunum (15 cm) were isolated from Wistar rats with vascular pedicle (superior mesenteric artery, SMA and portal vein). The SMA was cannulated with polyethylene tubing and flushed with 10 ml of University of Wisconsin (UW) preservation solution. The intestinal lumen was rinsed with 10-15 ml of UW solution and the organ was stored immersed in UW solution at 4 degrees C for 4 or 18 h. After cold ischemic storage structural and functional integrity of the preparation was tested by biluminal perfusion with artificial buffer via SMA (5 ml/min modified Krebs-Henseleit buffer, 200 mg% glucose, 5% dextran 78, 0.06 mg% dexamethasone, 7 mg% atropine to counteract paralytic hypersecretion) and the intestinal lumen (0.5 ml/min NaCl 0.9% with 200 mg% of galactose). The in vitro model was validated by perfusion of control preparations harvested without ischemic alteration. It was seen that ischemic preservation of 4 h had only a minor impact on the recovery of cellular ATP content and enzyme release (LDH) upon reperfusion, whereas both parameters were significantly changed after 18 h of preservation. Functional parameters like transmucosal carbohydrate absorption and luminal water balance, however, were significantly impaired already after 4 h of ischemic storage of the gut, thus yielding sensitive criteria for the appreciation of the postischemic integrity of the gut.

Conclusions: It is concluded that the isolated gut preparation, being an inexpensive and technically feasible model, may be a useful tool in experimental research of intestinal ischemia/reperfusion.