ACUTE EXPERIMENTAL GLOMERULAR NEPHRITIS IN RABBITS: A CORRELATION OF MORPHOLOGICAL AND FUNCTIONAL CHANGES

THE MECHANISM BY WHICH EXPERIMENTAL NEPHRITIS IS PRODUCED IN RABBITS INJECTED WITH NEPHROTOXIC DUCK SERUM

1. Glomerulonephritis was produced in rabbits by the injection of antirabbit-kidney duck serum. 2. The clinical and pathologic characteristics of the disease are discussed. 3. It was found possible by appropriate means either to accelerate the development of the nephritis or to prevent its appearance entirely. 4. An apparent correlation was found between the development of the nephritis and the formation of antibodies to duck serum by the injected rabbit. 5. The generally accepted concept of the mechanism of the disease does not appear to be in accordance with the facts here observed. A new hypothesis is presented.

Diffuse glomerulonephritis produced in rabbits by massive injections of bovine serum gamma globulin

A high incidence of acute diffuse glomerulitis was produced in unilaterally nephrectomized rabbits by injection with two successive doses of purified bovine serum gamma globulin (fraction II). This experimental nephritis is morphologically analogous to human acute and subacute diffuse glomerulonephritis. The technique described is advanced as a valuable experimental method in the study of the pathogenesis of glomerulonephritis. Qualitative immunological investigations produced no evidence that the pathogenesis of experimental globulin nephritis is mediated by kidney autoantibodies. The rôle of hypersensitivity in the pathogenesis of nephritis is discussed. During the 1st week of the development of experimental globulin nephritis there is a significant increase in blood coagulability, as shown by a lowering of the mean coagulation time in globulin-treated animals during this period. This observation has not been reported previously. The possible relation of this increased blood coagulability to the formation of coagula in the glomerular capillaries is discussed. The injection of a single purified antigen (bovine serum gamma globulin) produced three distinct types of lesion, diffuse glomerulitis, focal granulomata of the heart valves and valve rings, and coronary arteritis.

Experimental serum disease; a pathogenetic study

The intravenous injection of one large dose of serum into rabbits caused a variety of changes of considerable complexity. 1. There was an immediate proliferation of mesenchymal cells, including plasma cells, particularly in heart, lungs, and spleen. 2. The signs of serum disease developed only at the time of abundant antibody formation, before significant quantities of antibody were laid down in the vascular connective tissue. 3. Allergic arteritis, marked glomerular nephritis, myocardial necrosis, and Aschoff body-like structures were seen only after hypersensitivity had developed. It appears that most, if not all, of these pathological alterations were true Arthus phenomena. 4. There were at least two distinct varieties of allergic arteritis and glomerular nephritis, namely a proliferative one, following the first injection, and a a necrotizing one, seen only after 2 injections. It appears that the first was a subacute Arthus phenomenon, while the latter was an acute Arthus phenomenon superimposed on a subacute one. The subacute experimental glomerular nephritis resembled the intracapillary glomerulonephritis in man, while the acute variety was like human extracapillary glomerular nephritis.

Experimental globulin glomerulonephritis in rabbits; morphological and functional changes

Diffuse glomerulonephritis was induced in unilaterally nephrectomized albino rabbits by giving them two massive intravenous injections of purified bovine serum gamma globulin. Morphologically, these renal lesions were similar to those of human acute and subacute glomenilonephritis. Globulin nephritis in rabbits also closely resembles experimental nephritis induced by injection of other foreign proteins. The course of this experimental disease was characterized by abrupt onset of proteinuria, hematuria, elevation of serum globulin, and reduction of albumin. Uremia developed in some animals. The manifestations of nephritis during life coincided with the development of demonstrable antibodies to the injected globulin. In view of the similarities between experimental globulin nephritis in rabbits and human nephritis, together with common features with other experimental nephritis, it is suggested that all may have a common pathogenetic mechanism. It is concluded that quantitative antibody response may be of greater importance in the pathogenesis of nephritis than antigen specificity.

Glomerular lesions and the nephrotic syndrome in rabbits given saccharated iron oxide intravenously; with special reference to the part played by intracapillary precipitates in the pathogenesis of the lesions

Intravascular precipitates, comprised at least in part of iron, formed regularly in rabbits given one or more injections of a saccharated iron oxide preparation intravenously, and these lodged in numerous capillaries throughout the body, particularly those of the lungs and kidneys. Large numbers of the brownish precipitates remained in the capillaries of the renal glomeruli during the first few days following injection of the iron, but most of them disappeared after 5 to 7 days, with only moderate amounts of brown pigment remaining in the endothelial cells of the renal glomeruli. Signs of acute injury of the glomerular tufts-namely) pyknosis of some of the endothelial cells, margination of leukocytes within the glomerular capillaries, and slight proliferation of the epithelial cells-also developed some 5 to 7 days following injection of the iron, along with marked proteinuria, which proved transitory if no further injections were given. When the iron preparation was given repeatedly over prolonged intervals, however, the proteinuria persisted and became extreme, and hypoproteinemia developed, often with hypercholesterolemia and transitory edema as well. Histological studies of the kidneys of rabbits manifesting the nephrotic syndrome, as just described, disclosed that virtually all the renal glomeruli were greatly altered, mainly owing to proliferation of the epithelial cells, together with some fibrosis and atrophy. Some of the rabbits having marked proteinuria and other functional changes eventually developed azotemia following repeated injections of the iron, and several of them lost weight and died; the renal glomeruli of these animals showed changes like those just described, but the alterations were more extensive. Considered together, the findings provide evidence that the intravascular precipitates first occluded the glomerular capillaries for a period of several days following injection of the iron and then largely disappeared from them just prior to the development of morphologic signs of glomerular injury and proteinuria. Hence the possibility was considered that the intracapillary precipitates might have produced acute injury to the walls of the glomerular capllaries through the agency of anoxia. But it is plain that the findings of the present study do not disclose the essential nature of the anatomical change responsible for the proteinuria, or the means whereby this was produced. The findings as a whole were briefly considered in relation to the pathogenesis of the nephrotic syndrome as it occurs naturally in human beings.