Cellular and subcellular demonstration of mercury in situ by modified sulfide-silver technique and photoemulsion histochemistry.

Young adult C57BL/6J mice were injected with 4.0 mg/kg body wt of methylmercuric chloride (MMC) for 3 consecutive days for a total of 12.0 mg/kg. Control animals received physiological saline in place of MMC. One week following the last injection, the animals were sacrificed. Representative tissue blocks and sections from the brain, kidney, and liver were subjected to a modified sulfide-silver technique (SST) and the photoemulsion histochemical method. The results show that both of these techniques demonstrate consistent and distinct localization of mercury (Hg) gains in cells and subcellular organelles. These methods are based on the principle that Hg compounds react strongly with sulfhydryl groups in tissues and cells to form Hg-sulfides and also on the affinity of Hg and silver to form an amalgam when placed in a physical developer or photographic emulsion. Thus Hg in cells is demonstrable without prior treatment of sulfide solution. The methods are simple and reliable when used with proper controls. Specific localization of Hg in cells in situ without the use of radioactive material and without disruption of anatomical relationships provided by these methods offers distinct advantages over other methods of Hg determination. Thus it would be possible to conduct a retrospective or prospective study of human autopsy materials and also would allow direct correlation of Hg deposition with pathological changes in cells and subcellular organelles.