Ultrastructural and x-ray analytical studies on intranuclear bismuth inclusions

Area of Science:

• Nephrology
• Toxicology
• Electron Microscopy

Background:

• Bismuth compounds are used therapeutically but can cause toxicity.
• Kidney tubules are a primary site for excretion and potential accumulation of xenobiotics.
• Intranuclear inclusions are cellular structures of varying composition and significance.

Purpose of the Study:

• To investigate the ultrastructural characteristics of intranuclear inclusions formed in rabbit kidney tubules following parenteral administration of bismuth subnitrate.
• To determine the elemental composition of these inclusions using electron-probe analysis.

Main Methods:

• Rabbits were administered bismuth subnitrate parenterally.
• Kidney tissues were processed for electron microscopy using glutaraldehyde and osmium tetroxide fixation.
• Unstained sections were examined under electron microscopy.
• Electron-probe analysis was performed on the inclusions.

Main Results:

• Parenteral bismuth subnitrate administration induced intranuclear inclusions in renal tubules.
• Inclusions appeared homogeneous after glutaraldehyde fixation and granular/fibrillar after osmium tetroxide fixation.
• Inclusions were electron-dense and disappeared under focused electron beam, indicative of bismuth.
• Electron-probe analysis confirmed the presence of bismuth and suggested possible sulfur co-localization.

Conclusions:

• Parenteral bismuth subnitrate leads to the formation of intranuclear inclusions in rabbit kidney tubules.
• The observed electron density and beam interaction phenomena are consistent with bismuth deposition.
• Electron probe analysis definitively identified bismuth within these inclusions, with a potential role for sulfur.