Sudan Black and Osmic Acid as Staining Agents for Testicular Interstitial Cells

Two standard cytological techniques have heen modified to stain specifically the interstitial cells of the testis. In Method 1, the tissue is fixed in Zenker-formol or Regaud's fluid for several hours or overnight and subsequently postchromed in 3% K₂Cr₂O₇ for 72 hr at 37°C. After paraffin embedding, sections are cut at 5μ, dewaxed, brought down to 70% alcohol and stained in an unfiltered saturated solution of Sudan black in 70% alcohol for 10-30 min. Sections are washed briefly in 70% alcohol to remove all excess dye, differentiated, if necessary, in 50% alcohol, downgraded to water and mounted in Farrants' medium or glycerol jelly. Interstitial cells: deep blue black; remainder of testicular tissue: light blue. Method 2 is essentially the Champy-Kull technique but specific staining for mitochondria is omitted and the sections are downgraded to water; then they are mounted in Farrants' medium or glycerol jelly without further treatment. In this way osmicated lipoids are preserved. Interstitial cells: conspicuous due to the variable number of black granules in their cytoplasm; the remainder of the tissue: yellow.