Inhibition of Influenza-Virus-Induced Apoptosis in Chorion Cells of Human Fetal Membranes by Nordihydroguaiaretic Acid

Abstract

Objectives: It has been postulated that the pathogenesis of influenza virus infection involves not only the virus-proliferation-mediated apoptotic cell death in infected cells, but also a direct reactive oxygen species (ROS)-induced cellular injury in the infected organs. We examined effects of an antioxidant, nordihydroguaiaretic acid (NDGA), on apoptosis induction and viral proliferation. Subsequently, the results were compared with those of pyrrolidine dithiocarbamate (PDTC), another antioxidant. Methods: The levels of ROS production were measured with 2′,7′-dichlorofluorescein diacetate; apoptosis induction and viral proliferation were analyzed by DNA fragmentation and plaque-forming assays, respectively. Results: The treatment of infected cells with NDGA inhibited ROS overproduction, apoptotic DNA fragmentation and virus proliferation. The maximum inhibition against DNA fragmentation (76%) was observed with 500 µM NDGA. The antiviral activity of NDGA against influenza virus was more potent than that of PDTC. Conclusions: The present study, therefore, suggests for the first time that NDGA, a known antioxidant reagent, inhibits the induction of apoptosis in human fetal membrane chorion cells infected with influenza virus through the more potent antiviral activity than that of PDTC.