N-乙酰半胱氨酸体外对流感病毒H1N1的抑制作用

目的探讨N-乙酰半胱氨酸（N—acetylcysteine，NAC）在体外对流感病毒H1N1的抑制作用。方法采用MTT法、鸡胚接种法和免疫荧光法，观察NAC对流感病毒HlM的抑制作用。采用血球凝集试验、神经氨酸酶活性抑制试验和透射电镜负染技术，初步探讨NAC对流感病毒HlM的抑制机制。结果NAC在MDCK细胞上的最大无毒剂量是6．25mg／mL；流感病毒H1Nl在MDCK细胞上的半数致死感染浓度（TCID-50）为1012-2.25／100μ；在三种作用途径下（治疗性给药、预防性给药和直接灭活后给药），NAC明显抑制了流感病毒HlNl对MDCK细胞的感染，细胞存活率分别为91．88％、93．21％、94．67％，在对照组，流感病毒H1N1感染后的细胞存活率为28．32％，两者相比差异有统计学意义（P〈0．05）；免疫荧光结果显示，与病毒对照组形成的强特异性荧光相比，三种作用途径感染MDCK细胞后的特异性荧光明显减弱；鸡胚培养法的结果显示，NAC明显抑制了流感病毒H1N1在鸡胚内的增殖，实验组血凝效价低于1：2，对照组血凝效价为1：1024；神经氨酸酶活性抑制试验和透射电镜的结果显示，NAC能够明显抑制流感病毒川N1的神经氨酸酶活性，对流感病毒H1N1的病毒体结构也有明显的破坏作用。结论NAC在体外对流感病毒川N1有明显的抑制作用，其抑制机制可能与NAC对流感病毒血凝素和神经氨酸酶活性抑制及病毒体的直接破坏有关。

Inhibitory effects of N-acetyl cysteine on influenza virus HI N1 in vitro

Objective To explore the inhibitory effects of N-acetylcysteine （NAC） on influenza virus H1N1 in vitro. Methods MTF test, the immunofluorescence test and the chick embryos inoculation test were used to detect the inhibitory effects of NAC. The neuraminidase activity inhibition test, blood agglutination test and transmission electron microscope （TEM） assay were used to detect the inhibition mechanmism of NAC in vitro. Results The maximum non-toxic dose of NAC in MDCK cells was 6.25 mg/mL; The TCIDs0 of influenza virus H1N1 on MDCK cell was 10 -2.25/100 μL; The survival rates of MDCK cells were 91.88% , 93.21% and 94.67% respectively in three different administration modes of NAC （treatment, prevention and direct inactivation modes） by MTT assay, while the cell survival rate in virus control group was 28.32%. The difference of these results was statistically sig- nificant （P 〈 0.05）. MDCK cells infected with H1N1 virus showed stronger specific yellowish-green immunofluo- rescence compared to the cells treated with N-acetyl cysteine in treatment, prevention and direct inactivation modes. In chick embryo culture test, the H1 N1 virus hemagglutination titer in the NAC treatment group was signifi- cantly lower than the virus control group, which was less than 1 ： 2 in the NAC treatment group and 1 ： 1024 in thevirus and solvent control groups. The inhibition rate of neuraminidase activity in NAC treatment group was higher than 80% , while the inhibition rates in the H1N1 control group and the solvent group were lower than 20%. TEM result showed that NAC had obvious damage effect on the structure of influenza virus H1N1. Conclusion NAC has obvious inhibitory effects on the influenza virus H1N1 in vitro. The inhibition mechanism of NAC may be relat- ed to the activity inhibition of the hemagglutinin and neurarninidase and the direct damage effect to virus particles of influenza virus HI NI.