-induced glial cell death is apoptotic
(A) IFNγ treated oligodendrocytes have pyknotic nuclei. Oligodendrocytes were treated with IFNγ for 18 hr and then stained with the O1 antibody detected with FITC-conjugated goat anti-mouse IgM (left panel). Nuclei were counterstained with Hoechst dye (right panel). The figure shows the same field of an IFNγ-treated culture. Arrow head indicates a cell with normal morphology with O1 staining but a pyknotic nucleus with Hoechst stain (bar = 10 µm). (B) DNA fragmentation in IFNγ treated cultures. Oligodendrocytes were cultured as described in the methods section. Begining on Day 2 of culture, cells were treated with PBS for 48 hr (Lane 1) or IFNγ for 24 and 48 hr (Lanes 2 and 3, respectively). Soluble DNA fragments were isolated and resolved on a 1.2% agarose gel, transfered to a Gene Screen Plus membrane, and probed with 32P-labeled rat genomic DNA. The membrane was exposed to film for 12 hr and the autoradiograph is shown. Bars at right represent the following sizes in base pairs from top to bottom: 9416, 2322, 872, 310, and 192.