title: Tumor necrosis factor alpha immunoreactivity of rat peritoneal mast cell granules decreases during early secretion induced by compound 48/80: an ultrastructural immunogold morphometric analysis.
abstract: We used fast (seconds) and ultrafast (milliseconds) microwave energy-assisted chemical fixation protocols, postembedding immunogold staining, and a morphometric analysis to investigate the early morphological changes and the TNF-alpha immunoreactivity in the cytoplasmic granules of rat peritoneal mast cells that had been stimulated to secrete by exposure to compound 48/80. Exposure to compound 48/80 induced the development of increased numbers of cytoplasmic granules that exhibited decreased electron density; these granules often also appeared swollen. These granule alterations were accompanied by a significantly decreased proportion of granules that were positive for TNF-alpha immunoreactivity. We also calculated the density of TNF-alpha labeling/mu 2 in both dense (unaltered) and altered granules in specimens. TNF-alpha immunoreactivity was present in dense granules (regardless of whether or not the specimens had been stimulated with compound 48/80) and in cells that were fixed with either fast or ultrafast microwave energy. However, altered granules exhibited a decreased density of TNF-alpha label. These findings show that changes in the immunolocalization and/or density of TNF-alpha immunoreactivity occur very rapidly upon stimulation of rat peritoneal mast cells with compound 48/80.
authors.affiliation: Department of Pathology, Beth Israel Hospital, Boston, Mass., USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Beil
authors.forename: G R
authors.initials: GR
authors.lastname: Login
authors.forename: M
authors.initials: M
authors.lastname: Aoki
authors.forename: L O
authors.initials: LO
authors.lastname: Lunardi
authors.forename: E S
authors.initials: ES
authors.lastname: Morgan
authors.forename: S J
authors.initials: SJ
authors.lastname: Galli
authors.forename: A M
authors.initials: AM
authors.lastname: Dvorak
mesh_terms: D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D010529:Peritoneal Cavity / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
chemical_list: D014409:Tumor Necrosis Factor-alpha; D003189:p-Methoxy-N-methylphenethylamine