RESUMO
Exposure to titanium dioxide nanoparticles [TiO[2] NPs] results from its wide use in the fields of medicine, industry, engineering, and environmental technology. To investigate the effect of administration of TiO[2] NPs on the ultrastructure of the rat liver and renal cortex. Rats were subdivided into two groups: group A [served as control] and group B [TiO[2] group]. TiO[2] was suspended in PBS and administered by an oral gavage to the rats of group B daily for 90 days at a dose of 5 mg/kg body weight. Thereafter, group B was subdivided into group B1 and sacrificed 24 h after the last dose of titanium. Group B2 was left untreated for 12 months and then sacrificed. Specimens from the liver and renal cortex were obtained and processed for examination by transmission electron microscopy. Histopathological changes were detected in the hepatocytes of group B1 in the form of dilated rough endoplasmic reticulum, numerous lysosomes, and abnormal mitochondria. Moreover, accumulation of large lipid droplets and wide cytoplasmic vacuoles was observed. The renal cortex was also affected. Numerous lysosomes were observed in the lining cells of the proximal tubules and the glomerulus showed an apparent increase in the number of mesangial cells. The interstitium was the site of excessive collagen bundles. These hepatic and renal cortical changes were partially ameliorated 12 months after the last dose of TiO[2]. Small doses of TiO[2] NPs for a long duration resulted in a variety of degenerative changes in the rat liver and renal cortex. Therefore, further studies are required to investigate the underlying mechanisms of this toxicity and to search for possible protective measures