Quantitative particle-induced X-ray emission imaging of rat olfactory epithelium applied to the permeability of rat epithelium to inhaled aluminum

Neurotoxicity from chronic metal inhalation has been suggested as an underl ying contributor to late-developing neurodegenerative diseases that have sy mptoms similar to Alzheimer's and Parkinson's syndromes. If inhaled metals contribute to pathogenesis of these diseases, identifying, localizing, and quantitating metal deposition(s) within specific target regions of the cent ral nervous system will be critical to our understanding of the mechanisms. Standard analytical techniques used to date require exposure to extremely high concentrations of metals to meet analytical detection limits in small tissue areas. The relevance to lower-dose environmentally relevant exposure s and potential protective barriers is therefore questionable. The feasibil ity of microbeam particle-induced X-ray emission is investigated as a metho d for rapidly scanning tissues to study the inhalation of metals, nasal per meability, and central nervous system deposition. The optimal beam spot and analysis time used to image the rat olfactory epithelium to facilitate the rapid detection of aluminum localizations were determined. Measurements of aluminum localizations in rat olfactory bulb and brain sections are also p resented.