Histochemical Alterations Revealed by Tetrazolium Chloride in Hypertensive Kidneys in Relation to Renal VEM Mechanisms.

Abstract

The present study is concerned with the histochemical appearance of kidneys of normal and hypertensive animals and human subjects after treatment of the tissues with 2,3,5-triphenyl tetrazolium chloride (TTC). The incubation of slices of renal cortex with TTC has disclosed patterns of formazan deposition (reduced TTC) in the proximal convoluted tubules with striking differences between normal and hypertensive kidneys. In the proximal convoluted tubules of kidneys from normotensive animals and man, the formazan is deposited as fine dust-like granules, evenly distributed within the cytoplasm. In the hypertensive kidney, the formazan is deposited in coarse clumps, plaques or needles, commonly at the cell margins and often extracellularly as well. Despite the difference in formazan patterns, the total amt. of reduced TTC per mg. of kidney tissue is approx. the same in normal and hypertensive animals, as is the oxygen consumption determined by the conventional micro-respiration technic. Concurrent studies of VEM metabolism show the uniform restriction of VEM production to anaerobiosis in normal kidneys, and the formation of VEM under both anaerobic and aerobic conditions by the hypertensive kidney. The association of histochemical changes in the proximal convoluted tubules with alterations of the VEM mechanisms in experimental and human hypertension suggests that the proximal tubules may be the site of VEM formation, and that the failure of the hypertensive kidney to limit VEM formation to anaerobiosis may be related to the enzymatic disorganization revealed by TTC.