FIG. 5.

Neuropathological changes in ataxic Tg(PrP61) mice. Nerve cell loss and degeneration in the hippocampus of a spontaneously sick, 21-day-old Tg(PrP61)Prnp^0/0 mouse. Bars, 100 μm (A) and 50 μm (D). Panels B through D are identical in magnification. (A) Hematoxylin and eosin stain shows loss of pyramidal cells in the proximal CA₁ region and degenerating neurons in the distal CA₁ region. (B) Anti-glialacidic fibrillary protein immunostain of the distal CA₁ region shows intense reactive astrocytic gliosis. (C) Intraneuronal cytoplasmic PrP61 inclusions in neurons of the distal CA₁ region revealed by the hydrolytic autoclaving method for protease-resistant PrP using MAb 3F4 as previously described (33). (D) In situ end labeling utilizing the Apoptag kit (Intergen) as previously described (1). Positive labeling of cells is suggestive of apoptosis. No apoptosis was seen in sections from age-matched, non-Tg Prnp^0/0 mice.