FIG 5.

Lycorine protects mice against HCoV-OC43 infection. (A) Kaplan-Meier survival curves of mice >20 days after intranasal inoculation of HCoV-OC43, followed by treatment with the indicated inhibitors (n = 6/group). Inhibitor doses and regimens were selected based on their acute toxicity (emetine was used at 5 mg/kg, chloroquine was used at 30 mg/kg, and the other inhibitors were used at 15 mg/kg). (B) Viral loads in the mouse brain and spinal cord treated with lycorine. Twelve-day-old female BALB/c mice were inoculated via the intranasal route with 100 TCID₅₀ HCoV-OC43-WT and treated with lycorine or DMSO control for 3 days. At 72 h postinfection, viral loads in the mouse brain and spinal cord were determined by qRT-PCR. Data represent the mean ± standard deviation (error bars) of the results of three independent experiments. (C) IHC analyses of brain tissue from mice treated with lycorine. Twelve-day-old female BALB/c mice were inoculated via the intranasal route with 100 TCID₅₀ HCoV-OC43-WT and treated with lycorine or DMSO control for 3 days. Mouse brain coronal sections were stained for HCoV-OC43 N (green) and nuclei (blue).