Renal microradiography of experimental ureteral obstruction in the rabbit

Microradiography of nephrons in kidneys perfusion-fixed with glutaraldehyde permits examination of large numbers of nephrons. This technique was applied to rabbits between one and 14 days following unilateral ureteral ligation. Kidneys without ureteral occlusion served as controls. By two days after ureteral obstruction there was dilatation of the ducts of Bellini and papillary collecting ducts. At three to four days there was splaying and tortuosity of the loops of Henle. By eight to 10 days the proximal straight tubules were noted to be dilated and helically twisted. After two weeks of ureteral obstruction there was dilatation of Bowman's space with encroachment on the glomerular capillary tuft. At this time many proximal convoluted tubules began to show atrophic changes. These morphologic alterations may due in part to back pressure on the nephrons, with retrograde progression as the duration of urinary tract obstruction is increased. The distal convoluted tubule and the descending limb of the loop of Henle were not noted to be abnormal during the study.