RECONSTRUCTION OF BLOOD-FLOW DISTRIBUTION IN THE RAT-KIDNEY DURING POSTISCHEMIC RENAL-FAILURE

Inner medullary blood flow has been found to remain nearly unchanged d uring postischemic renal failure, despite a severely disturbed perfusi on in the outer medulla. In order to elucidate this discrepancy, rats were subjected to 1 h left renal artery occlusion and 1 h reflow. The blood plasma was then labelled by dye-conjugated globulin for 1 min. T he in vivo indicator distribution was histologically analyzed, especia lly in the medullary vascular bundles. The filling there was observed along a section plane positioned through the inner stripe along the lo ng and the short axis of the organ. Vessels centrally located within t he bundles were more labelled than those in the periphery of the bundl es. In addition, the degree of filling on the whole was almost twice a s high in the tissue near the renal sinus as in the central area. At t he same time, filling defects in the renal papilla were restricted mos tly to the center of that tissue. The observations support the assumpt ion that differences in blood flow obstruction exist within each bundl e. They also show that perfusion defects of the outer medulla occur mo re readily in the center of the organ, thus allowing blood to enter th e inner medulla via vascular bundles located marginally, adjacent to t he renal sinus of the kidney.