纳米银抗3型副流感病毒作用及机制研究

目的: 研究纳米银抗3型副流感病毒(parainfluenza virus 3, PIV3)的作用，并初步探讨其作用机制。 方法： 采用细胞培养技术、MTT法和免疫荧光法，分析纳米银对PIV3感染狗肾细胞(MDCK)的预防作用、治疗作用以及对PIV3的直接灭活作用；通过神经氨酸酶活性抑制实验，观察纳米银对PIV3神经氨酸酶活性的影响；利用透射电镜(TEM)负染技术观察纳米银对病毒形态结构的直接影响；小鼠体内实验，观察纳米银对鼠肺组织病理变化的影响。结果： 纳米银作用后（治疗给药组、预防给药组和直接灭活组）MDCK存活率分别为93.05%，90.32%，94.81%，与病毒对照组（25.50%）相比，差异均有统计学意义(P均<0.01)；与病毒对照组形成的强特异性荧光相比，纳米银作用后(治疗给药组、预防给药组和直接灭活组)MDCK特异性黄绿色荧光明显减少；纳米银作用组对PIV3神经氨酸酶活性的抑制率均高于80%，而病毒对照组和溶剂作用组的抑制率低于20%；纳米银对PIV3形态结构的破坏作用随着时间的延长而增加；纳米银治疗组的肺组织与正常肺组织比较相近，病变较轻，而病毒对照组的肺组织出现水肿，炎性浸润，形态结构消失。结论： 纳米银对PIV3具有明显的抑制作用，其机制可能与纳米银破坏病毒粒子结构及抑制神经氨酸酶活性有关。

Potential mechanism and inhibitory effects of silver nanoparticles on parainfluenza virus type 3

Objective: To explore the inhibitory effects and the potential mechanism of silver nanoparticles against parainfluenza virus type 3(PIV3). Methods: Cell culture, MTT test assay and immune fluorescence assay were applied to evaluate the anti PIV3 activities of silver nanoparticles in preventing, treating and directly inactivating. The neuraminidase activity inhibition test was used to study the inhibitory effect of silver nanoparticles on PIV3 neuraminidase activity; destructive effect of silver nanoparticles on PIV3  was observed by transmission electron microscope (TEM); murine experiment was performed to observe the pathological changes of mouse lung tissues in vivo. Results: The survival rates of canine kidney cells(MDCK) were 93.05%，90.32% and 94.81%, respectively, under three different administration(treatment to medicine group, preventive medication group, direct inactivating group) of silver nanoparticles by MTT assay, while the cell livability in control group was 25.50%, the differences were statistically significant (P<0.01). MDCK cells infected with PIV3 had more specific yellowish green immunofluorescence  compared with the cells treated with silver nanoparticles in virucidal, antiviral and inactivating ways. The inhibition rate of neuraminidase activity on silver nanoparticles treatment group was higher than 80%, while the PIV3 control group and the solvent group were lower than 20%. The results of TEM showed that silver nanoparticles had an obvious destructive effect on PIV3 in a time dependence. Compared with the normal lung tissues, the pathological changes in the mice treated with the silver nanoparticles were similar or less severe, while the lung tissues from the virus model group presented with edema, inflammatory cell infiltrating and morphological structure disappearing. Conclusion: Silver nanoparticles had remarkably inhibitory effects on PIV3 and the possible mechanisms may be associated with the neuraminidase inhibition and virion damage by silver nanoparticles.