The effects of green tea and propolis extracts on pro-inflammatory cytokines TNF-α, IFN-γ, IL2, and immunoglobulin production in experimentally infected rabbits with bovine herpesvirus-1

Abstract

Bovine herpesvirus 1 (BHV-1) is a highly contagious viral pathogen which causes infectious bovine rhinotracheitis in bovine worldwide. Currently, there is no antiviral prophylactic treatment available capable of the complete cure of the viral disease and facilitating recovery from latent infection in animals. The present study aimed to evaluate antiviral activities of Water Green Tea Extract (WGE) and Ethanol Propolis Extract (EPE) against BHV-1 virus comparing to commercial Acyclovir (ACV) in vitro in Madin-Darby Bovine Kidney (MDBK) cell line and in vivo in rabbits as a laboratory animal's model. The cytotoxicity assay was determined the safe dose of water green tea, and Ethanol propolis extracts and evaluated antiviral activity of each extract on infected MDBK with BHV-1. The fifteen rabbits were divided accidentally into five groups. Groups 1, 2 and 3 were inoculated with BHV-1 virus 107 TCID50/250 ul in nostrils and received propolis ethanol, water green tea extracts and ACV antiviral for 7 dpi respectively. Group 4 was inoculated with BHV-1 virus 107 TCID50/250 ul in nostrils without extracts or commercial drug. Group 5 was considered as control negative. Results of in-vitro study showed water green tea, and ethanol propolis extracts were potent inhibitor on BHV-1, which showed 80% protection against this virus and dropped in viral titer more than ACV. In vivo study of treated infected animals with WGE, EPE and ACV reduced clinical signs, elevated cytokines, and antibody production levels and failed re-isolated or detect DNA in blood or nasal samples swabs. Non treaded infected rabbits group developed respiratory clinical signs, humoral response and re-isolated BHV-1 and detected viral DNA of BHV-1 in blood, and nasal swabs from experimentally infected rabbits. In conclusion, propolis and green tea extracts were able to prevent virus replication and reduced CPE in MDBK cell cultures infected with BHV-1 and able to induce cytokines and antibodies levels production.