Acta Veterinaria et Zootechnica Sinica ›› 2024, Vol. 55 ›› Issue (11): 5287-5298.doi: 10.11843/j.issn.0366-6964.2024.11.044

• Clinical Veterinary Medicine • Previous Articles     Next Articles

Evaluation of the Inhibitory Activity of Folium Isatidis Aqueous Extract on the in vitro Proliferation of Infectious Bovine Rhinotracheitis Virus

Qi FENG1,2(), Yigang LIU1,2, Qin HE1,2, Zelong LI1,2, Yingcai MA1,2, Pengfei YI1,2, Na LI1,2, Yawei SUN1,2, Rulong CHEN3, Gang YAO1,2,*(), Xuelian MA1,2,*()   

  1. 1. College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi 830052, China
    2. Xinjiang Key Laboratory of New Drug Research and Creation for Herbivores, Urumqi 830052, China
    3. Xinjiang Tianlai Breeding Limited Liability Company, Bole 833400, China
  • Received:2024-01-11 Online:2024-11-23 Published:2024-11-30
  • Contact: Gang YAO, Xuelian MA E-mail:fengqi0103@163.com;yg@xjau.edu.cn;13699381790@163.com

Abstract:

We aimed to investigate the inhibitory activity of Folium Isatidis aqueous extract on the in vitro proliferation of infectious bovine rhinotracheitis virus (IBRV), and to provide new reference data for the clinical treatment of IBRV infection. The cytotoxic effects of Folium Isatidis aqueous extract on Madin-Darby bovine kidney (MDBK) cells were assessed using cell counting kit-8 (CCK-8) and MTT assays, alongside the cytopathic effect (CPE) method, to establish the maximum safe concentration (MSC). The MSC was subsequently diluted in a three-step, two-fold serial dilution to evaluate the extract's inhibitory action on IBRV through both MTT and CCK-8 assays across various administration modes. Metrics such as cell viability, drug efficacy, 50% cytotoxic concentration (CC50), and 50% effective concentration (EC50) were calculated, employing the Therapeutic Index (TI) as a principal evaluative criterion. The inhibitory effect of Folium Isatidis aqueous extract on the proliferation of IBRV was further confirmed by viral titration, real-time quantitative PCR, and immunofluorescence assays. The findings indicate that the MSC of Folium Isatidis aqueous extract on MDBK cells is 0.8 μμL―1, with a CC50 of 1.937 μμL―1. The antiviral efficacy enhances with increasing concentrations within the MSC range. The extract exhibited significant inhibitory effects on IBRV across different administration modes, pre action of medicine and virus, inoculate virus first and then add medicine, add medicine first and then inoculate virus, with EC50 values of 0.292 8, 0.350 1, and 0.416 1 μμL―1, respectively, and corresponding TIs of 6.615 4, 5.532 7, and 4.655 1. Notably, the maximal viral suppression was observed at 36 hours post-infection when the extract was pre-mixed with the virus, as evidenced by real-time fluorescence quantitative PCR and immunofluorescence staining. The aqueous extract of Folium Isatidis demonstrates potent anti-IBRV activity, providing a scientific foundation for its clinical application and further development in veterinary medicine. This study contributes valuable insights into the antiviral properties of Folium Isatidis, underscoring its potential as a therapeutic agent against IBRV infections.

Key words: Folium Isatidis aqueous extract, infectious bovine rhinotracheitis virus (IBRV), in vitro antiviral, real-time fluorescent quantitative PCR, immunofluorescence staining

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