HISTOLOGY OF RAT SMALL-BOWEL TRANSPLANTS - CYCLOSPORINE-A AMELIORATESFEATURES OF REJECTION INCLUDING APOPTOSIS AND GANGLION-CELL REDUCTION

The histology of rat small bowel transplants (SET) was examined in ort hotopic isografts and allografts with and without immunosuppression. L ewis to Lewis isografts were examined 7 days after transplant, and LBN F1 to Lewis allografts were examined 2, 4, 7, and 10 days after transp lant; one group received cyclosporine A (CyA), and their allografts we re examined 7 days after transplant. Compared with similar intestinal segments from unoperated animals, allografts at 4, 7, and 10 days afte r surgery showed progressive inflammation, cryptitis, villous atrophy, and transmural necrosis. In contrast, SET in animals given CyA did no t significantly differ from normal in any histological parameter. The number of apoptotic structures per 100 crypts in SET at day 4 (58.25 /- 32.98) and day 7 (31.86 +/- 27.63) after transplant were significan tly increased compared with unoperated bower (5.23 +/- 13.41) (P < .05 ); the number in CyA-treated allografts (11.57 +/- 29.56) did not diff er significantly from normal. The number of intermyenteric ganglion ce lls was significantly reduced (P < .05) in allografts 7 and 10 days af ter transplant (mean and [range] = 31 [18 to 38] and 25 [23 to 27], re spectively) but the number in allografts from CyA-treated animals (47 [24 to 72]) did not differ from unoperated bowels (52 [30 to 88]). We conclude that CyA treatment significantly reduces the histological abn ormalities associated with transplant rejection including adverse effe cts on epithelial and ganglion cells; therefore, the absorptive capaci ty and motility characteristics of the CyA-treated SET should be prese rved compared with untreated allograft controls. Copyright (C) 1997 by W.B, Saunders Company.