Hippophae rhamnoides polysaccharides dampen pseudorabies virus infection through downregulating adsorption, entry and oxidative stress

Pseudorabies virus (PRV) is an alpha herpesvirus that causes pseudorabies. After 2011, new and more pathogenic PRV variants have caused huge economic losses to the pig industry. In addition, people have been reported to be infected with PRV. Therefore, developing new anti-PRV drugs is of great significance. In this study, we investigated the anti-PRV activity of Hippophae rhamnoides polysaccharides (HRP) in vitro. We found that HRP could significantly inhibit the infectivity of the PRV XJ5 strain in PK15 cells. Addition of HRP at different times of the virus life cycle mainly led to the inhibition of the adsorption and entry of virus into the cells. Our results revealed that HRP can reduce the malondialdehyde (MDA) content and reactive oxygen species (ROS) level in PRV-infected PK15 cells and increase the superoxide dismutase (SOD) activity. These results suggested that HRP can reduce PRV infection-induced oxidative stress. Therefore, HRP may act as an antiviral drug against newly emerging PRV variants.