Abstract：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 antiPIV3 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 yellowishgreen 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 timedependence. 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.
2013, Vol. 23 
