Identification of rat alveolar type II epithelial cells with a tannic acid and polychrome stain

Alveolar type II epithelial cells are identified by the presence of characteristic lamellar inclusions visualized by transmission electron microscopy. We developed a tannic acid and polychrome stain that can visualize these intracellular inclusions in rat alveolar type II cells by light microscopy and that can be used for autoradiography. This method of staining and fixation provides more cellular detail than other methods that use light microscopy.