Protection effects of mice liver and lung injury induced by coronavirus infection of Qingfei Paidu decoction involve inhibition of the NLRP3 signaling pathway.

Ethnopharmacological Relevance: Coronavirus Disease 2019 (COVID-19) is a grave and pervasive global infectious malady brought about by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), posing a significant menace to human well-being. Qingfei Paidu decoction (QFPD) represents a pioneering formulation derived from four classical Chinese medicine prescriptions. Substantiated evidence attests to its efficacy in alleviating clinical manifestations, mitigating the incidence of severe and critical conditions, and reducing mortality rates among COVID-19 patients.

Aim Of The Study: This study aims to investigate the protection effects of QFPD in mice afflicted with a coronavirus infection, with a particular focus on determining whether its mechanism involves the NLRP3 signaling pathway.

Materials And Methods: The coronavirus mice model was established through intranasal infection of Kunming mice with Hepatic Mouse Virus A59 (MHV-A59). In the dose-effect experiment, normal saline, ribavirin (80 mg/kg), or QFPD (5, 10, 20 g/kg) were administered to the mice 2 h following MHV-A59 infection. In the time-effect experiment, normal saline or QFPD (20 g/kg) was administered to mice 2 h post MHV-A59 infection. Following the assessment of mouse body weights, food consumption, and water intake, intragastric administration was conducted once daily at consistent intervals over a span of 5 days. The impact of QFPD on pathological alterations in the livers and lungs of MHV-A59-infected mice was evaluated through H&E staining. The viral loads of MHV-A59 in both the liver and lung were determined using qPCR. The expression levels of genes and proteins related to the NLRP3 pathway in the liver and lung were assessed through qPCR, Western Blot analysis, and immunofluorescence.

Results: The administration of QFPD was shown to ameliorate the reduced weight gain, decline in food consumption, and diminished water intake, all of which were repercussions of MHV-A59 infection in mice. QFPD treatment exhibited notable efficacy in safeguarding tissue integrity. The extent of hepatic and pulmonary injury, when coupled with QFPD treatment, demonstrated not only a reduction with higher treatment dosages but also a decline with prolonged treatment duration. In the dose-effect experiment, there was a notable, dose-dependent reduction in the viral loads, as well as the expression levels of IL-1β, NLRP3, ASC, Caspase 1, Caspase-1 p20, GSDMD, GSDMD-N, and NF-κB within the liver of the QFPD-treated groups. Additionally, in the time-effects experiments, the viral loads and the expression levels of genes and proteins linked to the NLRP3 pathway were consistently lower in the QFPD-treated groups compared with the model control groups, particularly during the periods when their expressions reached their zenith in the model group. Notably, IL-18 showed only a modest elevation relative to the blank control group following QFPD treatment.

Conclusions: To sum up, our current study demonstrated that QFPD treatment has the capacity to alleviate infection-related symptoms, mitigate tissue damage in infected organs, and suppress viral replication in coronavirus-infected mice. The protective attributes of QFPD in coronavirus-infected mice are plausibly associated with its modulation of the NLRP3 signaling pathway. We further infer that QFPD holds substantial promise in the context of coronavirus infection therapy.