Histological Study of Gender Differences in Accumulation of Silver Nanoparticles in Kidneys of Fischer 344 Rats

The tissue distribution of silver (Ag) nanoparticles showed a dose-dependent accumulation of Ag in all the tissues examined, including testes, kidneys, liver, brain, lungs, and blood. However, a gender-related difference in the accumulation of Ag was noted in the kidneys, with a twofold higher concentration in female kidneys compared males after subacute exposure to Ag nanoparticles via inhalation or oral ingestion. To investigate the gender-specific accumulation of Ag nanoparticles in kidneys of Fischer 344 rats, detailed histopathological studies were conducted by Ag enhancement staining. Female rats showed a higher accumulation of Ag nanoparticles in all kidney regions, including cortex, outer medulla, and inner medulla. In particular, the glomerulus in the cortex contained a higher accumulation in females than males. The Ag nanoparticles were also preferentially accumulated in the basement membranes of the renal tubules in the cortex, middle and terminal parts of the inner medulla, and outer medulla. In addition, Ag nanoparticles were detected in the cytoplasm and nuclei of interstitial cells in the inner medulla of the kidney.