Intrarenal hemodynamics in the transplanted rat kidney

Regional and single glomerular blood flow conditions in the transplanted rat kidney after various periods of cold ischemia were investigated with use of the microsphere method. Intravascular injection of a silicon rubber compound (Microfil) allowed identification and sampling of single glomeruli. The periods of ischemia were two hours (minor damage), 12 hr (intermediate damage), and 16 hr (severe damage). After two hours of cold ischemia, the regional and total renal blood flows were fairly normal. After 12 hr and 16 hr of cold ischemia, the total and regional blood flows were reduced five minutes after recirculation, the reduction being pronounced in the deep cortex and juxtamedullary glomeruli. In the 12-hr group, the blood flow showed complete restitution after 65 min, whereas in the 16-hr group, the blood flow in the inner cortex and juxtamedullary glomeruli remained decreased. An impairment of medullary circulation would seem to be an important component in the pathophysiology of acute renal failure in this model.