STUDY ON URANYL NITRATE-INDUCED ACUTE RENAL FAILURE

Abstract

The initial change with time, which is considered important in the study of the mechanism of acute renal failure, was investigated by using uranyl nitrate (abbreviated as UN in the following) induced acute renal failure model. The change in renal cortical sulfhydryl (SH) group in the initial stage of the disease was investigated with GSH which is considered to protect protein-SH group so that the relation between the change in SH group and the functional and morphological changes might be clarified. The relation between the renal functional and morphological changes as well as the presence of the the protective effect of EDTA in the initial stage of acute renal failure were investigated with EDTA, heavy metal chelating agent. The result is as follows.
1. With UN administration alone, glomerular filtration rate (GFR) and renal tubular sodium reabsorption rate were decreased accompanied with significant decrease in the content of soluble protein-SH group. Pretreatment with GSH significantly checked the decrease in the soluble protein-SH group content. However, GFR was reduced. Since there was no relation between the content of soluble protein-SH group and GFR, SH group might not be responsible for the decrease in GFR induced by UN.
2. Intravenous injection of EDTA immediately after UN administration showed a protective effect against acute renal failure.
3. Swelling of glomerular endothelial cell and decrease in endothelial fenestrae were observed by the morphological study on the following 3 groups: 1) Group in which only UN as administered; 2) Group which had pretreatment with GSH before UN administration; 3) Group which had intravenous injection of EDTA 20 minutes after UN administration. Remarkable and irregular thickening of the inner transparent layer of the glomerular basement membrane due to the deposit of amorphous material and the decrease in GFR were also noted in those groups. On the other hand, the characteristic change found in the glomerular capillary loop was rarely seen in the group which had intravenous injection of EDTA immediately after UN administration, suggesting the protective effect of EDTA against the decrease of GFR.
4. The relation between the functional change and the morphological change may suggest that the characteristic morphological change in the glomerular capillary loop has some relation to the glomerular filtration which may cause the decrease in GFR.