中文摘要：

目的探讨外源性一氧化氮（NO）对日本血吸虫尾蚴的体外杀灭效果及NO抑制剂对这种杀灭作用的阻断效果。方法收集日本血吸虫感染性钉螺体内尾蚴,用RPMI 1640培养液配制成浓度为1 000条/ml的尾蚴悬液。向尾蚴悬液中加入不同浓度的NO发生剂亚硝基铁氰化钠（SNP）,同时设不加SNP的对照组,观察外源性NO对尾蚴的杀灭作用及量效关系。向尾蚴悬液中加入2.00 mmol/L SNP,并加入4种NO抑制剂血红蛋白（Hb）、L半胱氨酸（L cyst）、左旋精氨酸（L arg）和硫酸亚铁（FeSO4）及其不同组合,同时设2.00 mmol/L SNP阳性对照组,观察抑制剂及其不同组合对NO杀灭尾蚴作用的阻断效应。结果经0.06、0.10 mmol/L和0.20 mmol/L SNP作用后,日本血吸虫尾蚴死亡率分别为（8.3±1.1）%、（6.26±2.3）%和（9.3±1.0）%,与对照组尾蚴死亡率差异无统计学意义（P〉0.05）;经0.50、1.00 mmol/L和2.00 mmol/L SNP作用后,尾蚴死亡率分别为（23.5±3.9）%、（46.0±1.1）%和（59.4±0.5）%,均显著高于对照组的尾蚴死亡率（P〈0.05）。在加入2.00mmol/L SNP的同时分别加入Hb、FeSO4、L cyst、L arg、FeSO4＋L cyst、FeSO4＋L arg、L arg＋L cyst,日本血吸虫尾蚴死亡率分别为（30.1±1.2）%、（45.1±1.4）%、（31.1±1.3）%、（34.2±3.1）%、（47.8±2.0）%、（49.1±0.6）%、（44.2±0.1）%,与2.00 mmol/L SNP阳性对照组比较,尾蚴死亡率均显著下降（P〈0.05）。结论外源性NO对日本血吸虫尾蚴具有体外杀灭作用,NO抑制剂Hb、FeSO4、L cyst、L arg及其不同组合对这种杀灭作用均具有不同程度的抑制效应。

英文摘要：

Objective To explore the killing effects of exogenous NO on the cercariae of Schistosoma japonicum in vitro and the blocking effects of NO inhibitors. Methods The cercariae of S. japonicum were collected from naturally infected snails,and then formulated into a 1 000 cercariae/ml suspension with RPMI 1640 medium. The relationship between the killing effects and doses of exogenous NO on cercariae were investigated through the suspension with different concentrations of NO generating agents（SNP）and negative control（without SNP）. On the other hand,the blocking effects were also investigated through the suspensions being added 2.00 mmol/L SNP and four different NO inhibitors,Hb,FeSO 4,L-cyst,L-arg and their combination. Additionally, the appropriate positive（2.00 mmol/L SNP）and negative controls（without NO generating agent）were used. Results The mortality rates of cercariae were（8.3±1.1）%,（6.26±2.3）%,and（9.3±1.0）% in the SNP 0.06,0.1 and 0.2 mmol/L groups,respectively,and there were no statistically significant differences between the blank control group and the above-mentioned three groups, respectively（P 0.05）. The mortality rates of cercariae were（23.5±3.9）%,（46.0±1.1）%,and（59.4±0.5）% in the SNP 0.50, 1.00 and 2 mmol/L groups,respectively,and there were statistically significant differences between the blank control group and the above-mentioned groups,respectively（P 0.05）. The mortality rates of cercariae were（30.1±1.2）%,（45.1±1.4）%,（31.1± 1.3）%,（34.2±3.1）%,（47.8±2.0）%,（49.1±0.6）%,and（44.2±0.1）% in the 2.00 mmol/L SNP suspensions which were added of Hb,FeSO 4,L-cyst,L-arg,FeSO 4 ＋L-cyst,FeSO 4 ＋L-arg,FeSO 4 ＋L-arg＋L-cyst,respectively. Compared with the 2.00 mmol/L SNP suspension,the mortality rates of the above-mentioned groups declined,and there were statistically significant differences（P 0.05）. Conclusion There are killing effects of exogenous NO on the cercariae of S. japonicum in vitro,and four different NO i