Biochemical alterations in rat Thiry-Vella fistulas

In order to obtain baseline information on the secretory function of normal rat bowel for our work on intestinal graft ischemia, we studied several bi ochemical parameters in rat Thiry-Vella fistulas (TVF). TVFs were created i n 200-g male Lewis rats (n=11) using the 25-cm segment of jejunum normally used as a graft in our intestinal transplant model. The stomas were matured primarily and the animals were allowed to recover. The TVFs were flushed a t 0, 6, and 24 h and then daily for up to 21 days with 12 mL normal saline solution. The effluent was collected and analyzed fbr total protein (TP), s ecretory phospholipase A(2) (sPLA(2)), intestinal fatty acid binding protei n (I-FABP), lactate dehydrogenase (LDH), and N-acetylglucosamine (NAGA). TP content was 0.12 +/- 0.01 mg/mL up to 48 h, then gradually increased and s tabilized at 0.39 +/- 0.05 mg/mL at day 21. By sodium dodecyl sulfate polya crylamide gel electrophoresis (SDS-PAGE), one major protein band was identi fied in the low-molecular-mass range (15 kD), consistent with I-FABP and sP LA(2). Secretory PLA(2) levels decreased over the first 4 days to a low of 115 +/- 24.8% hydrolysis/min/fraction, then gradually rose to a plateau at approximately 529.76 +/- 88.36% hydrolysis/min/fraction by day 18. I-FABP l evels rose rapidly from 0 ng/mL at 2 h to 900 +/- 250.0 ng/mL at 6 h and ap proximately 3000 +/- 304.9 ng/mL by day 14. LDH levels at 2 h and 48 h did not differ, with 0.03 +/- 0.004 and 0.03 +/- 0.005 optical density units (O D)/min/mL, respectively. NAGA levels were 0.07 +/- 0.05 OD/h/mL at 2 h and rose to 0.14 +/- 0.04 OD/h/mL at 48 h. These data suggest that after an ear ly equilibration period, biochemical secretion into the lumen of normal rat bowel reaches a state of equilibrium, and therefore appears to reflect the baseline biochemical status of the bowel. Some of these levels are not neg ligible as one would expect in "normal" bowel. This information should prov e extremely helpful as a baseline study of abnormal conditions of the intes tine, such as ischemia or rejection.