Basic fibroblast growth factor and granulocyte colony-stimulating factor enhance mucosal surface expansion after adult small bowel transplantation without vascular reconstruction in rats.

AIM

We showed previously that adult small bowel could be transplanted successfully in rats without vascular reconstruction by removing the graft serosa. In this study, we assessed if granulocyte colony-stimulating factor (G-CSF) or basic fibroblast growth factor (bFGF) could improve graft survival in the same rat model.

METHOD

A 10-mm-long adult small bowel graft from an adult 12-week-old Lewis rat was transplanted into a pouch created in the omentum of a 5-week-old Lewis rat (syngeneic bowel transplantation [SBTx], n = 49). Graft serosa was removed just before SBTx in the serosectomy group (n = 29) and left intact in the nonserosectomy group (n = 20). Each group was divided into 3 subgroups (sG): sG-1 had no G-CSF or bFGF; sG-2 had daily subcutaneous injections of G-CSF; and sG-3 had continuous infusion of bFGF around the graft in the omentum. All grafts were harvested 14 days after SBTx and studied histologically. A mucosal surface expansion score (MSES) was used where 0 = no mucosa on the graft, 1 = mucosa on one fourth of the graft, 2 = mucosa on one half of the graft, 3 = mucosa on three fourths of the graft, and 4 = mucosa on the whole graft. The density of CD34-positive capillaries per 1000 nuclei was also measured.

RESULTS

Serosectomy group MSES were significantly higher than nonserosectomy group MSES indicating that grafts survived (P < .0001). CD34-positive capillaries in serosectomy group subgroups for mucosa were 103.9 +/- 34.2, 130.2 +/- 52.0, and 132.3 +/- 37.7, respectively; for muscle, 74.4 +/- 38.0, 86.2 +/- 32.9, and 82.4 +/- 30.3, respectively; and for omentum, 73.8 +/- 30.1, 151.3 +/- 60.3, and 140.0 +/- 49.0, respectively. Mucosal surface expansion score and overall CD34-positive capillaries for sG-2 and sG-3 were significantly higher than for sG-1 (both, P < .05).

CONCLUSION

Our results suggest that G-CSF and bFGF enhance angiogenesis and mucosal surface expansion.