EFFECT OF SMALL-BOWEL TRANSPLANTATION, DENERVATION AND ISCHEMIA ON RAT INTESTINAL MICROFLORA

The effects of denervation and warm ischaemia on quantitative and qual itative changes in small intestinal microflora following rat heterotop ic small-bowel isotransplantation were assessed. Animals with Thiry-Ve lla fistula, but without transplants, acted as controls. Thirty and 40 -fold increases in bacterial colony counts were seen in the isografts compared to controls at 2 and 7 days, respectively (P < 0.05). Aerobic faecal organisms predominated at 2 and 7 days, but an overgrowth of F lavobacterium meningosepticum occurred at 28 days in the transplanted and host bowels. The effect of warm ischaemia on intestinal microflora was assessed by the application of a microvascular clamp to the super ior mesenteric artery for 90 min. The effect of denervation was assess ed following microsurgical division of all nervous tissue around the s uperior mesenteric artery. After 7 days, lengths of jejunum and ileum were removed and intraluminal microflora assessed. The number of bacte rial colonies isolated from the ileum in the warm ischaemia group was six times greater than the number in the control group, whereas no sig nificant changes were seen in the upper bowel. In contrast, denervatio n led to a slight, but consistent, decrease in colony counts. These fi ndings suggest that the increase in bacterial numbers in an isografted small bowel primarily results from warm ischaemia rather than from me senteric denervation, and that physical aspects of the procedure may a ffect the development of sepsis following small-bowel transplantation.