Histochemical localization of copper in various organs of brindled mice

In order to disclose histochemically the localization of copper in various organs in Menkes disease, untreated brindled mouse hemizygotes (BM) and normal male littermates were examined by the modified sulfide silver method of Kozma, where the specificity for copper staining has been proved to be enhanced by trichloroacetic acid treatment. When compared with normal controls, renal tubules--most of which were of proximal convoluted segments--and intestinal mucosal epithelium of BM clearly showed increased staining with copper. Hepatocytes in the liver and neurons in the brain, however, displayed an obvious reduction in staining despite a marked increase in staining of capillaries in these two organs. Electron microscopy of the specimens stained with the Kozma method revealed numerous fine silver grains which represented Cu++ localization, distributing within the cytoplasm outside both mitochondria and the nucleus. The intense staining of capillaries observed only in the liver and brain of BM may indicate a blockade of copper transport owing to trapping of copper in the capillary walls, and may be responsible for low tissue-copper concentrations of the two organs. Similarly, high tissue-copper concentrations of the kidney and intestine are attributed to excessive deposition of copper in their epithelial cells which are probably due to impaired intracellular copper-transportation.