Abstract
Objective
The present study aimed to establish a cerebral schistosomiasis model in rabbits, to provide a valuable tool for morphological analysis, clinical manifestation observation, as well as investigations into immunological reactions and pathogenesis of focal inflammatory reaction in neuroschistosomiasis (NS).
Methods
Sixty New Zealand rabbits were randomly assigned into operation, sham-operation and normal groups. Rabbits in the operation group received direct injection of dead schistosome eggs into the brain, while their counterparts in the sham-operation group received saline injection. Rabbits in the normal group received no treatment. Base on the clinical manifestations, rabbits were sacrificed on days 3, 5, 7, 10, 20, and 30 post injection, and brain samples were sectioned and stained with hematoxylin-eosin. Sections were observed under the microscope.
Results
The rabbits in the operation group exhibited various neurological symptoms, including anorexy, partial and general seizures, and paralysis. The morphological analysis showed several schistosome eggs in the nervous tissue on day 3 post operation, with very mild inflammation. On days 7–10 post operation, several schistosome eggs were localized in proximity to red blood cells with many neutrophilic granulocytes and eosinophilic granulocytes around them. The schistosome eggs developed into the productive granuloma stage on days 14–20 post operation. On day 30, the schistosome eggs were found to be in the healing-by-fibrosis stage, and the granuloma area was replaced by fibrillary glia through astrocytosis. The sham-operation group and the normal group showed negative results.
Conclusion
This method might be used to establish the cerebral schistosomiasis experimental model. Several factors need to be considered in establishing this model, such as the antigenic property of eggs, the time of scarification, and the clinical manifestations.
Keywords: experimental model, schistosomiasis, neuroschistosomiasis, granuloma
摘要
目的
本研究旨在建立家兔脑型血吸虫病模型, 为观察脑型血吸虫病的形态学和临床症状、 研究其免疫反应以及探讨其发病机理提供重要手段。
方法
新西兰大耳兔60只随机分成手术组(n=30)、 假手术组(n=20)和对照组(n=10)。 在手术组中, 直接将血吸虫虫卵悬浊液注入家兔大脑, 形成血吸虫虫卵肉芽肿。 假手术组采用相同的手术方式, 但是注入等剂量的生理盐水。 对照组不采用任何手术。 术后对动物神经系统临床症状进行观察, 并于第3、 5、 7、 10、 20和30天对家兔脑组织切片, 并进行苏木精-伊红染色观察。
结果
手术组家兔术后出现各种神经系统症状, 包括厌食、 局部抽搐、 全身抽搐以及瘫痪。 病理切片证实在术后第3天, 家兔神经系统中形成血吸虫虫卵肉芽肿, 并伴有轻微的炎症。 在第7–10天, 红细胞临近区域形成一些虫卵肉芽肿, 伴随有数量较多的中性粒细胞和嗜酸性粒细胞聚集在其周围。 在第14–20天, 虫卵肉芽肿主要处在增生期。 在第30天, 血吸虫虫卵肉芽肿处于纤维化治愈阶段, 肉芽肿区域逐渐被纤维性神经胶质细胞取代。 此外, 假手术组和对照组家兔术后表现正常, 病理切片未见明显异常。
结论
本方法可以成功建立脑型血吸虫病动物模型。 在实验中, 血吸虫虫卵的抗原性、 动物的临床表现以及实验动物的处死时间等因素十分重要。
关键词: 动物模型, 血吸虫病, 脑型血吸虫病, 肉芽肿
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