| Adenovirus was initially discovered in adenoidal tissue and belongs to DNA virus. Adenovirus infections are traditionally associated with respiratory, ocular, or gastrointestinal disease, occurring mainly in children and U.S. military recruits as endemic infections during outbreaks. Adenovirus infection may be associated with the growth of the immunocompr-omised population, such as AIDS, hematopoietic stem cell transplant (HSCT) recipients, severe combined immunodeficiency syndrome (SCID), bone marrow transplant (BMT) recipients, and so on. Adenovirus, because of its various species and high morbidity, has increasingly been recognized as significant viral pathogens. This has dramatically framed the urgent need for an effective systemic antiviral agent. Silver nanoparticles(Silver-nps) have been demonstrated significant microbicidal activity against both Gram-negative and Gram-positive bacteria. In addition, silver-nps have been proven to be virucidal in vitro against the human immunodeficiency virus, hepatitis B virus, monkeypox virus, herpes simplex virus type1and H1N1influenza virus. At present, there are no data demonstrating its antiviral activity against adenovirus in vitro. This has led to the present study in which the overall goal is to assess whether silver-nps have the inhibition effect against adenovirus type3(ADV3). Cell culture and immunofluorescence assay were applied to evaluate the anti-adenovirus activities of silver-nps in inhibiting the formation of ADV3progeny virions, preventing and inactivating ADV3. The anti-adenovirus activities of silver-nps on Hela cells were observed by transmission electron microscopy. The routine PCR and Real-Time PCR method were also used to analyze the destructive effect of silver-nps on ADV3DNA. The result suggests that TCo of silver-nps was52.48μg/mL. The median tissue culture infective dose(TCID50) of ADV3on Hela cell was10-2.74. In the range of non-toxic concentration, the50μg/mL of silver-nps and100TCID50of ADV3were analyzed in virucidal, antiviral and inactivating ways, the survival rates of Hela cells were (93.58±1.79)%,(90.50±1.99)%,(95.38±2.98)%respectively, when compared with the viability of control group, there was a significant difference statistically(P<0.01); Hela cells infected with ADV3had much specific immunofluorescence when compared to the cells treated with silver-nps in virucidal, antiviral and inactivating ways, which suggested that the silver-nps had inhibiting effect on ADV3. Compared to the intact shape of ADV3virions, it was observed that the silver-nps could directly interact with viral particles and cause damage to ADV3virions in a time dependent manner by transmission electron microscopy. The DNA of virions treated with silver-nps was amplified by PCR method and the value of DNA grayscale were decreased in comparison to the control group. The Real Time-PCR method was also applied to analyze ADV3DNA copies after the ADV3treated with silver-nps in different concentration, the result indicate that ADV3DNA load was decreased when compared to the group treated with solvent(P<0.05). Silver-nps have remarkably inhibiting effects on ADV3in vitro, their possible mechanisms indicate that silver-nps inactive ADV3by damaging the viral particles, capsid protein and dsDNA that govern life cycle processes occurring after host cell attachment. Breaking the enzyme of transcription process and DNA polymerase of replication are also the possible reasons. In conclusion, the efficient inhibitory activities of silver-nps against ADV3have been demonstrated at cellular and molecular level, which illustrate that silver-nps may play an important role in treatment and prevention of ADV3infection and provide experimental and theoretical basis for further study silver-nps as an antiviral agent. |
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