Electron Microscopic Studies of Transepidermal Absorption of Mercury

Abstract

Following the application of mercuric chloride to normal human skin, specimens were fixed in glutaraldehyde, exposed to ammonium sulfide and postfixed with osmium tetroxide. Abnormal electron-dense structures were observed in the epidermis in intracellular and extracellular sites below the stratum corneum. These were most often found in or near nuclei, mitochondria, on tonofilaments, and within membrane-bound inclusions. The dense structures observed after histochemical processing may represent mercury or mercury complexed with cell components within the deeper layers of epidermis.

Mercury forms an electron-dense amalgam with silver in photographic emulsions. Silver grains were seen electron microscopically over sections of mercury-treated skin which were coated with photographic emulsion and developed. The localization of these grains corresponded to the localization of electron-dense deposits seen after histochemical processing.