Résumé
Galectin-3 is a beta-galactoside-binding lectin that plays a role in neuroinflammation through cell migration, proliferation, and apoptosis. In the present study, regulation of galectin-3 was examined in the brain of mice infected with the Daniel strain of Theiler's murine encephalomyelitis virus (TMEV) at days 7 and 81 post-infection by immunohistochemistry. Immunohistochemistry revealed that galectin-3 was mainly localized in ionized calcium-binding adapter 1-positive macrophages/activated microglia, but not in Iba-1-positive ramified microglia. Galectin-3 was also weakly detected in some astrocytes in the same encephalitic lesions, but not in neurons and oligodendrocytes. Collectively, the present findings suggest that galectin-3, mainly produced by activated microglia/macrophages, may be involved in the pathogenesis of virus induced acute inflammation in the early stage as well as the chronic demyelinating lesions in Daniel strain of TMEV induced demyelination model.
Sujets)
Animaux , Souris , Apoptose , Astrocytes , Encéphale , Mouvement cellulaire , Maladies démyélinisantes , Encéphalomyélite , Galectine -3 , Immunohistochimie , Inflammation , Macrophages , Microglie , Neurones , Oligodendroglie , Theilovirus , VirusRésumé
Our original aim was to determine whether dBcAMP-induced activation of cultured astrocytes affected the course of subsequent viral infection. After 2 h exposure of 2-day-old first subculture of mouse astrocytes to dBcAMP 1 mM, cell monolayers grown in glass coverslips of Leighton tubes were inoculated with 10(3) PFU of Theiler virus-GDVII strain (TMEV-GDVII). At 9 days post-infection (pi), viral infectivity persisted in supernatants from dBcAMP-treated cultures, but was no longer detectable in non-stimulated controls. The relatively spared astroglial monolayer at day 1 pi, hardly affected by progressive viral cytolytic effect, was chosen for immunolabeled cell count, whether by viral antigen or GFAP. To this end, 20 fields for each coverslip were digitalized at 250x final magnification. In dBcAMP treated cultures, viral antigen(+) cells were fewer and lower in percentage versus infected cultures lacking stimulation. As regards GFAP staining, stimulation or infection per se induced a greater number and percentage of labeled astrocytes. According to morphometric characterization, such increase was due to a greater number of process-bearing astrocytes. It may be concluded that, regardless of previous dBcAMP treatment, early TMEV-GDVII infection enhanced immunocytochemical and morphological differentiation in cultured astrocytes.
Sujets)
Animaux , Souris , Astrocytes , Theilovirus , Antigènes viraux/analyse , Astrocytes , Dibutyryl AMP cyclique , Taille de la cellule , Cellules cultivées/effets des médicaments et des substances chimiques , Cerveau , Effet cytopathogène viral , Différenciation cellulaire/effets des médicaments et des substances chimiques , Prolongements cytoplasmiques/ultrastructure , Traitement d'image par ordinateur , Marqueurs biologiques , Souris de lignée BALB C , Protéine gliofibrillaire acide/analyse , TheilovirusRésumé
No abstract available.