东方田鼠和小鼠感染日本血吸虫后血清NO的变化以及肝、肺病变的比较

Alterations in the serum nitric oxide levels and comparison of the lesions in liver and lungs in mice or Microtus fortis infected with Schistosoma japonicum

目的了解日本血吸虫适宜宿主和非适宜宿主在感染后血清NO含量的变化规律以及肝、肺组织感染后的病变情况，以比较不同宿主对日本血吸虫感染的反应。方法东方田鼠和小鼠分别感染尾蚴1000条和40条，每2d分别剖杀2只，观察两宿主肝、肺变化，同时分别检测各宿主血清中NO的含量。结果小鼠和东方田鼠感染日本血吸虫后，肺部出现程度不同的出血现象。感染10d后出血现象均自行消失。其中，小鼠肝表观正常，但30d后肝中出现卵引起的内芽肿。东方田鼠在感染后6d肝中开始出现童虫所致病变，感染后第12～14d时逐渐减少，20d后病变消失。其间，小鼠和东方田鼠血清NO水平表现出不同的变化规律。东方田鼠感染后血清NO水平由正常的100μmol／L降到16μmol／L，18～20d恢复到原来的水平，完成一个完整和规律的循环。小鼠感染日本血吸虫后NO水平变化较大，第36d后，血清NO水平基本上维持在0～10μmol／L之间较低的、非正常水平。结论日本血吸虫非适宜宿主东方田鼠感染日本血吸虫后肝、肺病变特征以及NO水平变化与日本血吸虫适宜宿主小鼠不同，提示东方田鼠感染后体内存在一个敏感和系统的抗感染过程。

To understand the changes of serum nitric oxide （NO） levels and pathological changes in liver and lungs in permissive and non-permissive hosts infected with Schistosoma japonicum in order to compare the responses to infections induced in different hosts, Microtus fortis as well as mice were infected with 1000 and 40 eereariae respectively, and two of them in each group were killed every day to examine the serum levels of NO and the lesions in liver and lungs of the infected animals, It was found that different degree of bleedings occurred in lungs of each group of the infected animals, which disappeared spontaneously 10 days later. The liver of mice was almost normal except the granulomatous changes induced by eggs 30 days after infection, but in case of the infected M, fortis, the pathological changes induced by adult worms began to appear 6 days after infection,but gradually decreased from 12 to 14 days,and disappeared 20 days later. Synchronously, the NO level from sera of M. fortis showed an integrated and regular cycle, in which the serum NO level dropped from the normal value of 100 μmol/L to 16μmol/L, and turned to the original level within 18-9,4 days after infection. However, in case of mice infected, serum NO level varied a great deal, remaining at a low and abnormal levels of 0-10μmol/L at 36 days after infection. It is concluded that differences in the pathological changes in liver and lungs and the serum NO levels exist between the permissive and the non-permissive host（ mouse and M. fortis） infected with S. japonicurn, indicating that M. fortis may have a sensitive and systemic anti-Schistosoma japonicum effect after infection with this organism.