PLASMA-TO-LUMEN CLEARANCE OF PARA-AMINOHIPPURATE CAN REPLACE CR-51 EDTA CLEARANCE IN THE EVALUATION OF INTESTINAL MUCOSAL INJURY

Intestinal mucosal injury of various degrees occurs in many clinical s ituations and is initially evidenced by altered mucosal permeability. The latter may be assessed in animal models by determination of plasma -to-intestinal lumen clearance of specific molecules, usually chromate d Cr-51 EDTA, The purpose of this study was to evaluate the usage of p ara-aminohippurate (PAH) as a substitute for the commonly used radioac tive material, i.e., Cr-51-EDTA, in the evaluation of intestinal mucos al injury. An isolated loop of ileum was created in rats and constantl y perfused with warmed normal saline. Both renal pedicles were ligated . Either Cr-51-EDTA (18.5 Bq/kg) or PAH (58 mg/kg) was injected IV. Fi fteen-minute intestinal ischemia tvas produced by clamping the superio r mesenteric artery immediately after the end of an equilibration peri od. The perfusate was collected for 10 min prior to the initiation of intestinal ischemia, during the last 10 min of ischemia, and during th e following three 10-min periods of reperfusion. Blood samples were co llected at the end of each collection period for the determination of either PAH or Cr-51-EDTA concentrations and the calculation of either PAH or Cr-51-EDTA plasma-to-lumen clearances. PAH and Cr-51-EDTA plasm a-to-lumen clearances followed the same pattern in all five assessed p eriods with no statistical difference between the two. PAH plasma-to-l umen clearance is a feasible, reliable, and inexpensive method for the evaluation of ischemia/reperfusion injury to the intestinal mucosa. I t can safely replace the commonly used method in animal models that ut ilizes radioactive materials such as Cr-51-EDTA.