Development of arteriovenous shunts in rejecting rat kidneys

Arteriovenous shunts in rejecting rat kidneys were studied in vivo by injecting radiolabelled 15-micron microspheres into the graft artery 4-7 days after transplantation. Serum creatinine levels were measured and the transplants were examined microscopically. The radioactivity in the transplanted kidneys, lungs and the hind legs was recorded. A progressive increase in the amount of radioactivity found in the lungs started 5 days after allogenic transplantation but not after isotransplantation. Increased serum creatinine levels were first recorded on day 6 and focal necrosis or hemorrhages were not seen microscopically at any time. The results support the hypothesis that arteriovenous anastomoses are opened or created early as a part of the graft rejection process and not as a late consequence of tissue necrosis.