| [Abstract]Objective To investigate the pathological evaluation method of intrathalamic neurovirulence test of poliomyelitis vaccine in monkeys. Methods Rhesus monkeys were injected poliomyelitis vaccines into bilateral thalamus, the animals were sacrificed after observation of 21 days, the brain and spine were collected, after sectioning, dehydration, embedding, H.E. staining and gallocyanin staining, the tissues were observed under light microscopy, the pathological changes were scored, the severity of the pathological changes were determined by the score. 240 animals in 12 lots of vaccine evaluation were included in this study. Results The sections were taken from bilateral cerebellum (needle tracts included), midbrain, pons, medulla oblongata, the cervical enlargement, the lumbar enlargement. The pathologic changes were evaluated referring to the hemisection scoring method of intraspinal neurovirulence test, lesions on both sides of the brain stem, cervical enlargement and lumbar enlargement were scored, and the severity of the lesions of these three regions were determined according to the average score. We found that the total incidence of specific neuronal pathological changes was 15%. The incidences caused by different types of vaccines were similar. Minimal lesions were the most common, and severe lesions were mainly seen in type Ⅲ vaccine tests. Conclusions In intrathalamic neurovirulence test, scoring the lesions of nervous system by hemisections can objectively reflect the pathological changes of the nervous system. This method is easy to apply and can facilitate the unification of diagnostic criteria. We recommend this method to be used in pathological evaluation in intrathalamic neurovirulence test of poliomyelitis vaccine. |