Abstract
In this quantitative histochemical study, tissues were sectioned, then stained with procedures that conferred a metallic precipitate. Sections were photographed, removed from the slides, air-dried and weighed and then dissolved in acid and the metal content analyzed by atomic absorption spectrophotometry. The stains used in this study were the Alcian Blue (copper phthalocyanin) critical electrolyte concentration procedure on sections of the heart and duodenum from young male rats, colloidal iron on sections of the kidney from adolescent and senescent rats, silver impregnation on sections of the kidney of adolescent and senescent rats and an adenosine triphosphatase lead precipitation reaction on sections of the liver, kidney and heart from adolescent and senescent mice. The objective data obtained by the use of atomic absorption spectrophotometry, reported as micrograms of metal per milligram of dry weight of tissue, allowed statistical analysis of any differences in stain intensity of metallic dyes or metal-precipitating histochemical reactions. Attributes of atomic absorption spectrophotometry which make it desirable for use in this application include accuracy, ease of operation, low cost and ready availability.