Ultrastructural changes in renal proximal tubules after tetraethyllead intoxication

Tetraethyllead (TEL) has been shown to be both an occupational and an environmental hazard to human health. The present study investigates pathological changes in the kidney as a result of TEL poisoning. Rabbits were injected (ip) with 100–200 mg TEL, and controls were injected with an equal volume of normal saline solution. Animals were sacrificed upon onset of toxic symptoms (hyperirritation, tremor, and convulsion). Animals were perfused with 2.5% glutaraldehyde. Tissue samples from the renal cortex were obtained for electron microscopy. Pathological changes were not remarkable at the light microscopic level; however, electron microscopic examination revealed marked cytological changes in the epithelial cells of the proximal tubules (PT) of animals treated with TEL. Enlargement of apical vacuoles and accumulation of lysosomes and microbodies were promient findings in many PT epithelial cells. Many lysosomes appeared to be atypical in nature, displaying a high degree of pleomorphism in size, shape, and density. Giant lysosomes measuring 8–10 μm in diameter and crystalloid bodies within lysosomes were also observed. Configurational changes (increased convolution, branching, vesiculation, and degranulation) of the rough endoplasmic reticulum leading to the formation of honeycomb-like bodies were also found in many PT epithelial cells. The formation of the honeycomb-like bodies may represent a hyperplastic, hypoactive form of the rough endoplasmic reticulum and denotes a disruption of protein synthesis in these cells by TEL.