FIG. 5.

Loss of neurons, demyelination, and axonal degeneration detected in rats infected with PVC-211 MuLV at 21 dpi. Brain tissues from paralyzed rats infected as newborns with PVC-211 MuLV were compared with tissues from control rats injected with tissue culture medium at 21 dpi. Data are representative of two experiments; three control and three virus-infected rats were examined in each experiment. (A and B) Cresyl violet staining was carried out on sagittal sections of cerebellum and brain stem to identify neurons. Neurons (arrows) appear purple-blue when stained with cresyl violet, as described in Materials and Methods. Magnifications, ×20. (C) Neurons in CV stained sections of cerebellum or brain stem were enumerated; data are means ± standard errors of the means (P < 0.05). (D) Immunofluorescence with anti-NSE was assayed on sagittal sections of cerebellum to identify neurons, which stain green (arrows). Nuclei are counterstained with DAPI (blue). Different animals were used for CV and anti-NSE staining. Magnification, ×20. (E and F) Luxol fast blue staining for myelin fibers (arrows) of brain sections from the cerebellum and brain stem. Magnification, ×20. (G) H&E staining of cross-sections of muscle from the lower extremities of the hind limb. Representative muscle fibers are indicated by asterisks; arrows indicate the location of nuclei at the edge of or within muscle fibers. Magnification, ×10.