Catalase in salivary gland striated and excretory duct cells. III. Immunocytochemical demonstration with fluorescein and peroxidase-labelled antibodies

Antioxidant enzyme immunoreactivity in rat von Ebner gland after nickel treatment

Our study was designed to clarify the role of antioxidant enzymes in the rat von Ebner gland during acute nickel toxicity. After treatment with nickel acetate, we monitored ultrastructural alterations in acinar and ductal cells, immunohistochemical staining for glutathione peroxidase (GPx) and glutathione S-transferases (GST mu and GST pi), and immunoreactivity for malondialdehyde (MDA). Immunoreactivity for MDA was present only in the acinar cells, and it was enhanced at 3 h after Ni treatment. In contrast, immunoreactivities for GPx and GSTs did not change in acinar cells but significantly increased in ductal cells after Ni treatment. Cytoplasmic vacuoles increased in acinar cells at 3 h after Ni treatment, but they almost completely disappeared at 24 h. No morphological changes were observed in taste bud cells from Ni-treated rats. Because lipid peroxidation, as monitored by immunoreactivity for MDA, was only transiently increased in the acinar cells, the enhanced antioxidant enzyme immunoreactivity in ductal cells of the von Ebner gland plays a crucial role in the self-defense system against nickel toxicity in the rat oral cavity.

Enhanced immunocytochemical expression of antioxidant enzymes in rat submandibular gland after normobaric oxygenation

In order to clarify the role of antioxidant enzymes in the male rat submandibular gland against short-term normobaric oxygenation, we performed immunocytochemical staining of manganese-containing superoxide dismutase (Mn-SOD), copper- and zinc-containing SOD (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase, and glutathione S-transferases (GST alpha, GST mu, and GST pi) between days 1 and 7 after normobaric oxygenation. Ultrastructural alterations and immunoreactivities for malondialdehyde (MDA), a lipid peroxidation-related molecule, of the acinar and ductal cells after the oxygenation were also investigated. Immunoreactivity for MDA was exhibited in the acinar cells throughout the experiment. On the other hand, immunoreactivity for the SODs, CAT, and GSTs was not altered, when compared to that of controls, but was significantly elevated in the granular, striated, and excretory ductal cells. Since an increase of lipid peroxidation as indicated by enhanced immunoreactivity for MDA was detected in the acinar and intercalated ductal cells, the results indicate that the enhanced antioxidant enzymes in the granular, striated, and excretory ductal cells play a crucial role in the self-defense system of the male rat submandibular gland against normobaric oxygenation.

Immunofluorescent demonstration of myeloperoxidase of phi bodies and rods in leukaemic leucocytes

Previous studies employing enzyme histocytochemical methods based on the catalysis of the peroxidation of 3,3'-diaminobenzidine (DAB) demonstrated the presence of hydroperoxidase activity in phi bodies and rods of immature leucocytes of patients with active acute myelogenous leukaemia. It could not be determined from these studies whether the DAB oxidation product was demonstrating a single hydroperoxidase, catalase or myeloperoxidase, or both. In the present study, immunofluorescence techniques for the two hydroperoxidases were applied in an attempt to identify this activity specifically. The results obtained indicate that myeloperoxidase is present in the phi bodies and rods, and that this enzyme may be the major or the only hydroperoxidase present. Its activity could account for the peroxidation of DAB under conditions which are more favourable for the demonstration of catalase.