Glomerular and Juxta-Glomerular Lesions in Radiation Nephropathy

Endothelial cell damage progressing to extensive thrombosis of glomerular capillaries has been observed 1 to 12 months after fractionated, in situ X irradiation of murine kidneys with total doses ranging from 3000 to 5000 rad. These changes support the concept that radiation injures primarily glomeruli in mice. Because of the morphologic similarities (by light microscopy) between murine and human late lesions, it is likely that glomerular endothelial cell damage, and subsequent thrombosis, also occurs in humans. Unexpected alterations were found, again by electron microscopy, in the juxta-glomerular apparatus: the "epithelioid" cell granules often showed vacuolation, and osmiophilic deposits, as well as formation of large electron-dense crystals. These lesions in the juxta-glomerular granules may be related to radiation, to hypertension, or to both.