RESUMEN
ObjectiveThe human angiotensin converting enzyme2 （hACE2） transgenic mouse model was used to clarify the antiviral efficacy of BD-77 against a novel coronavirus SARS-CoV-2 and explore the action mechanism of BD-77 against SARS-CoV-2. MethodSARS-CoV-2 Omicron and Delta variant strains-infected VeroE6 cell models were established and administered with BD-77 to observe the antiviral effect of BD-77 in vitro. A kit was used to detect the effect of BD-77 in vitro on the binding of spike S protein of SARS-CoV-2 virus （Delta/Omicron） to angiotensin converting enzyme2 （ACE2）. Chromatography was adopted to detect the binding of BD-77 to the S protein and N protein of the novel coronavirus. hACE2 transgenic C57BL/6 mice were divided into a blank control group， SARS-CoV-2 infection group， BD-77 administration groups of 37.5 mg·kg-1 and 75 mg·kg-1， with eight mice in each group. The pneumonia model of SARS-CoV-2-infected hACE2 transgenic mice was built to observe the survival of the mice， detect the virus titer of the lung tissue of the mice， and observe the lesions in the lung tissue. ResultBD-77 had a certain inhibitory effect on Omicron and Delta variant strains in vitro， with median inhibitory concentration （IC50） of 526.3 mg·L-1 and 653.0 mg·L-1， respectively. BD-77 had no significant inhibitory effect on the binding of the S protein of WT， Omicron， and Delta variant strains of SARS-CoV-2 to ACE2 and had no binding effect with the S protein and N protein of the novel coronavirus. No mice in the blank group died， while the mortality rate of SARS-CoV-2-infected mice was 75%. There was a large amount of virus replication in the lung tissue of the mice and large areas of inflammatory infiltration in the lung tissue and interstitium. Compared with the model group， BD-77 administration groups of 37.5 mg·kg-1 and 75 mg·kg-1 could reduce the mortality of mice， significantly lower the virus titer in the lung tissue of mice （P<0.05）， and improve lung lesions. ConclusionBD-77 demonstrated significant inhibitory effects against SARS-CoV-2 virus in vitro and in vivo. However， its mechanism of action did not involve direct inhibition of the virus itself or intervention in the virus-host binding process. This finding suggests that the mechanism of action of BD-77 needs to be thoroughly investigated and elucidated by further experiments.
RESUMEN
ObjectiveTo observe the therapeutic effect of BD-77 by nebulized inhalation on animal models of various respiratory viral infections and investigate the mechanism of broad-spectrum antiviral action of BD-77 using proteomics. MethodThe influenza virus H1N1/FM1 experiment used ICR mice and divided them into a normal group， model group， Tamiflu group， and BD-77 groups of 75 and 37.5 g·L-1 for inhalation of 20 min and 25 min. Human coronavirus 229E and OC43 experiment divided the BALB/c mice into a normal group， model group， chloroquine phosphate group， and BD-77 groups of 75， 37.5， 18.75， and 9.375 g·L-1， with 10 mice in each group. Influenza virus H1N1/FM1 and human coronaviruses 229E and OC43 infection-induced pneumonia models were used to detect mouse lung index， and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the viral load in lung tissue. Enzyme-linked immunosorbent assay （ELISA） was used to detect related inflammatory factors in lung tissue， and proteomics analysis was performed on the lung tissue of OC43-infected mice. ResultCompared with that in the normal group， the lung index of mice in each infection group was significantly increased （P<0.01）， and viral nucleic acid could be detected in the lung tissue of mice infected with human coronaviruses 229E and OC43. The levels of interleukin-6 （IL-6）， IL-10， and tumor necrosis factor-α （TNF-α） in the lung tissue of mice infected with human coronavirus 229E were all significantly increased （P<0.01）. BD-77 could significantly reduce the lung index of mice infected with influenza virus H1N1/FM1 and human coronaviruses 229E and OC43 （P<0.05， P<0.01）， cut down the viral load in the lungs of mice infected with human coronaviruses 229E and OC43 （P<0.01）， and lower the contents of IL-6， IL-10， and TNF-α in the lung tissue of mice infected with human coronavirus 229E （P<0.01）. Proteomics analysis of the lung tissue of OC43-infected mice showed that BD-77 regulated the AMPK signaling pathway， TNF signaling pathway， NOD-like signaling pathway， IL-17 signaling pathway， Forkhead box protein O （FoxO） signaling pathway， transforming growth factor-β （TGF-β） signaling pathway， and other signaling pathways. ConclusionNebulized inhalation of BD-77 is effective in treating pneumonia caused by influenza virus H1N1/FM1 and human coronaviruses 229E and OC43 infection in mice and may exert its antiviral effects by regulating the balance of cellular metabolism， enhancing the immune function of the host， and attenuating inflammatory responses.