The Acute Changes in the Rabbit’s Kidney, Particularly the Pelvis, Produced by Ligating the Ureter

Abstract

The closer to the kidney the ureter was ligated the greater the tendency to hemorrhage. In one series, changes were observed after 1, 2, 4, 8, 12, 18, 24, and 48 hours. One animal in each time group had both ureters ligated, a 2nd had but 1 ligated. In experiments continued 3-28 days only the left ureter was ligated. Pelvic changes were: (1) hemorrhage, edema, and exudation of leucocytes, beginning after 4 hours and reaching a maximum in 18-24 hours; (2) destruction of parts of the epithelial lining, causing ulcers or deep sterile abscesses; (3) healing after 48 hours by proliferation of connective tissue cells and removal of the destroyed leucocytes by polyblasts; (4) healing of small lesions by formation of a pyogenic membrane, and lateral ingrowth of epithelium; (5) formation of small diverticula by action of the urine when large openings allowed it to penetrate the tissue; and (6) replacement of normal fat and connective tissue by dense fibrous connective tissue. Changes in the kidney proper were: (1) exceptionally, focal necrosis of the epi thelium with leucocytic infiltration; (2) once in this series, infarction of the kidney; and (3) necrosis of the tubules of the papilla, exceptionally with necrosis of the entire papilla. The relation of these experiments to the pathology of pyelitis in man may be summarized as follows: (1) certain hemorrhages (evidence of which is found after death) in the pelvis of the kidney following obstruction of the ureters may be attributed to pressure, not necessarily to infection; (2) formation of diverticula of the pelvis may give rise to a persistent sterile pyuria; (3) the products of acute inflammation can be so rapidly removed as to leave practically no trace after 14 days; and (4) the necessity of controlling results in experiments on injecting bacteria into the pelvis when the ureter is obstructed is evident; the presence or absence of infection does not affect the gross and microscopic appearance of hydronephrotic kidneys during the first 24 hours.