Ultrastructural renal lesions in goats given a lethal dose of imidocarb diproprionate

Ultrastructural renal lesions were studied in 20 goats given one intramuscular injection of a lethal dose of imidocarb diproprionate (6.75 mg/kg). The lesions were limited to proximal convoluted tubular epithelial cells and at postinjection (PI) hour 3 included: plasma membrane disruption, smooth endoplasmic reticulum proliferation and dilatation, swelling and increased electron density of mitochondria, and cytoplasmic ground substance rarefaction. At PI hour 12, disruption of plasma membranes, with fragmentation of the microvilli, loss of junctional complexes, and cellular detachments from in tact basement membranes were observed in many tubular epithelial cells. Mitochondrial configurational alterations became more prominent at 6 and 12 hours, with the formation of large membrane-bounded structures containing fragmented cristae, clear vacuoles, and amorphous matrical material. The intramitochondrial foci of electron-dense amorphous flocculent material, which was first observed at 6 hours and increased in electron density and in number by 12 and 24 hours, were probably comprised of denatured, clumped matrical protein. The 2nd type of intramitochondrial and cytoplasmic electron-dense deposit was observed PI hour 24. The basement membranes remained intact in most proximal tubules to support regenerating epithelial cells on PI day 4 and thereafter.