For sections, fixed explants were put into 0.4% paraformaldehyde in PBS overnight, equilibrated in 30% sucrose in PBS, and embedded in optimal cutting temperature compound (Fisher Scientific) in blocks and frozen at −80°C on dry ice. Frozen sections were cut at 5 μm. Slides were washed three times for 1 hour at room temperature in 0.1% Triton-X in PBS and then blocked for 1 hour at room temperature in 2% BSA in 0.1% Triton-X in PBS. Slides were incubated overnight at 4°C with rat monoclonal anti-mouse glial fibrillary acidic protein (GFAP; 1:100, gift from Albee Messing, University of Wisconsin-Madison, Madison, WI) and either rabbit polyclonal anti-mouse glutamate ammonia ligase (GLUL; 1:100, Abcam Inc., Cambridge, MA), chicken polyclonal anti-human CNTF (1:100, Pierce Biotechnology), goat polyclonal anti-mouse VEGF (1:100, R&D Systems), or goat polyclonal anti-human PEDF (1:00, Santa Cruz Biotechnology, Inc.). After washing three times in PBS at room temperature for 5 minutes, slides were incubated for 1 hour at room temperature in the dark with FITC-conjugated donkey anti-rat IgG (1:50, Sigma) and either rhodamine-conjugated rabbit anti-chicken IgG (1:300, Chemicon, Temecula, CA), Texas Red–conjugated rabbit-anti-goat IgG (1:300, Jackson ImmunoResearch Laboratories, Inc., West Grove, PA), or Texas Red–conjugated goat-anti-rabbit IgG (1:300, Jackson ImmunoResearch Laboratories, Inc.). All antibodies were diluted in 2% BSA in PBS. Slides were washed in PBS, incubated with 300 ng/mL 4′,6-diamidino-2-phenylindole (Pierce Biotechnology) in water for 10 minutes at room temperature in the dark, washed again with PBS, then covered with Immuno Mount and coverslipped.