一氧化氮对日本血吸虫童虫细胞毒作用的研究

Studies on Cytotoxicity of Nitric Oxide to Schistosomula of Schistosoma japonicum

目的研究一氧化氮(NO)对日本血吸虫童虫的杀伤作用.方法用LPS或LPS+IFN-γ诱导离体的小鼠腹腔巨噬细胞,使其产生NO;加入机械断尾的日本血吸虫童虫,测定48 h内童虫的死亡率.为进一步证实NO对童虫的杀伤作用,用诱导型一氧化氮合酶(iNOS)的抑制剂LNNA(Nω-nitro-Larginine)抑制NO的产生,与未加抑制剂组比较,观察童虫死亡率的变化.结果LPS或LPS+IFN-γ均能有效诱导巨噬细胞产生NO,2.0×105细胞产生的NO浓度分别为(109.96±3.70)μmol/L和(113.50±7.38)μmol/L,其相应的杀虫率分别达91.07%±2.92%和96.86%±2.36%.加入2 mmol/L的L-NNA后,巨噬细胞的NO产量明显降低,其杀虫率也相应减低.结论巨噬细胞诱生的NO对日本血吸虫童虫具杀伤作用.

Objective To study the in vitro larvicidal activity of nitric oxide (NO) to the juvenile Schistosoma japoni-cum. Methods Macrophages were induced by LPS or LPS + IFN-γ to produce NO, schistosomula obtained mechanically from cercariae were added to the medium with activated macrophages, the larvicidal activity was observed within 48 h . In order to further confirm the effect of NO, an inhibitor of iNOS,L-NNA (Nω-nitro-L-arginine), was used to inhibit the production of NO, larvicidal activity was measured by the same methods and the difference of dead larvae ratio was compared between the inhibited and uninhibited groups. Results LPS and LPS + IFN-γ can induce macrophages effectively, with the NO production of (109.96±3.70)μmol/L and (113.50±7.38) μmol/L respectively, accordingly the larvicidal effect reached to 91.07% ±2.92% and 96.86%±2.36% respectively. This activity can be inhibited by L-NNA. NO production and dead larvae ratio were reduced significantly in the inhibited group than in the uninhibited one. Conclusion NO produced by activated macrophages can kill schistosomula of Schistosoma japonicum.