Balb/c小鼠新孢子虫病动物模型的建立及在其体内发育过程的研究

Balb/c Mouse Model of Neosporosis and the Development Process with Infection of Neospora caninum

【目的】建立Balb/c小鼠感染新孢子虫的急性和亚急性发病模型,并研究新孢子虫在小鼠体内的发育过程。【方法】分别对两组小鼠腹腔接种新孢子虫8×106个/只和5×105个/只,接种后小鼠进行定时宰杀,取心、肝、肺、脑和后肢肌肉等进行组织病理学、免疫组织化学和PCR检测。【结果】发现Balb/c小鼠感染后病理变化主要表现为各器官组织的广泛性出血,非化脓性脑炎和肝细胞空泡变性。接种后第16天观察到脑组织内包囊,在其它组织中未观察到包囊样结构。PCR检测结果显示,接种后12h即可检测到肺脏和心脏组织内的新孢子虫特异性基因Nc-5,脑内最早于第8天检测到。接种25d后在肝脏、肺脏和脑内仍能检测到新孢子虫基因。综合观察和检测结果,发现新孢子虫对肝脏、肺脏和脑组织有一定的组织亲嗜性;雄性小鼠对新孢子虫更为敏感。【结论】成功建立了新孢子虫感染Balb/c小鼠的急性和亚急性发病的动物模型;跟踪观察了新孢子虫在小鼠体内各器官组织出现时间、持续时间以及分布的规律,初步掌握了新孢子虫在其体内发育的动态过程。

[ Objective ] The main purpose of the current study was to construct a Balb/c mouse model of N. caninum infection in both acute phase and subacute phase, and to study the development process ofN. caninum in mouse. [Method] In this research, Balb/c mice were divided into two groups, each group was inoculated with 8× 10^6 tachyzotie/mice and 5×10^5 tachyzotie/mice, respectively. Mice were euthanatized at different time points. Tissues of heart, liver, lung, brain and muscle were used for pathological, immuohistochemicai and microbiological examination. [Result] Both of the two groups were characteristed with vacuolar degeneration of the hepatocyte, hemorrhage in the lung and other visceras, nonsuppurative inflammation and necrosis in the brain. Cysts could be found in the brain 16 d after inoculation, and no cyst was observed in other tissues. The result of PCR revealed that N. caninum specific gene Nc-5 could be detected in lung and heart 12 h after inoculation, 8 d in brain. Nc-5 gene still could be detected in liver, lung and brain 25 d post infection. A tissue predilection to liver, lung and brain was found according to the results of histopathological examination. And male mouse showed more susceptivity to N. caninum than female did. [ Conclusion ] Acute and subacute N. caninum infection models were successfully built up in BALB/c mice. The spread of tachyzoites among the tissues was traced in the mouse model, and the dynamic process ofN. caninum infection in BALB/c mice was discovered.