Scanning electron-microscope studies of the endothelium of aortic allografts in the rabbit: effect of azathioprine, prednisolone and promethazine on early cellular invasion.

Aortic allografts in rabbits were observed by scanning electron microscopy 24 hr after transplantation. The extent of the leucocytic invasion could be precisely and reproducibly measured. Azathioprine and prednisolone, whether alone or in combination, given on three occasions--10 hr before, immediately after and again 10 hr after surgery, significantly inhibited the cellular invasion. Promethazine produced a slight, but not statistically significant, effect.