Hogan R N, Baringer J R, Prusiner S B
Lab Invest. 1981 Jan;44(1):34-42.
Scrapie is considered a prototype of the spongiform encephalopathies. This group of diseases is characterized by a prolonged incubation period, without symptoms, followed by an insidious onset of clinical disease leading to death. Attention has mainly been focused on central nervous system pathology, and reports of pathology in the retina have been limited. In this study, hamsters were inoculated intracerebrally with the scrapie agent and serially sacrificed to determine agent titers and pathologic changes in the eyes over time. Scrapie infectivity rises progressively in the eye to maximal levels between 6 and 8 weeks after inoculation, then it reaches a plateau. Ocular abnormalities are first visible 8 weeks after infection. The process begins with a gradual loss of rod outer segments, after which progressive loss of rod inner segments and photoreceptor nuclei occurs. By 10 weeks, only a vestige of the outer nuclear layer remains. Ultrastructurally, this destruction is attended by the presence of macrophages, although the importance of this finding is unknown. Later, Müller cells increase their pericellular investment of remaining photoreceptor cell nuclei. The limitation of the lesion to the outer retinal layers suggests this tissue site may be important in the investigation of basic pathogenetic mechanisms in the spongiform encephalopathies.
羊瘙痒病被认为是海绵状脑病的一个原型。这类疾病的特点是潜伏期长，没有症状，随后临床疾病隐匿发作并导致死亡。人们主要关注中枢神经系统病理学，而视网膜病理学的报告有限。在本研究中，将羊瘙痒病病原体脑内接种到仓鼠体内，并连续处死仓鼠以确定随着时间推移眼睛中的病原体滴度和病理变化。羊瘙痒病感染性在眼睛中逐渐上升，在接种后6至8周达到最高水平，然后达到平稳期。眼部异常在感染后8周首次可见。这个过程始于视杆细胞外段逐渐丧失，之后视杆细胞内段和光感受器细胞核逐渐丧失。到10周时，仅残留外核层的遗迹。在超微结构上，这种破坏伴随着巨噬细胞的出现，尽管这一发现的重要性尚不清楚。后来，米勒细胞增加了对剩余光感受器细胞核的细胞周围包裹。病变局限于视网膜外层表明该组织部位在海绵状脑病基本发病机制的研究中可能很重要。
