[Protective effect of Forsythiae Fructus extract on mice with herpes simplex encephalitis]

This study aims to explore the protective effect of Forsythiae Fructus extract(FFE) against herpes simplex virus encephalitis(HSE) in mice. To be specific, life extension rate of mice, viral load in mouse brain, levels of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), and interferon-α(IFN-α), and nitric oxide(NO) content in mouse brain were determined. Mice were classified into normal group, model group, acyclovir(ACV) group, and high-dose, medium-dose, and low-dose(100, 50, 25 mg·kg~(-1), respectively) FFE groups. HSE was induced in mice in corresponding groups. Then, the life extension rate was compared among groups. Viral load in brain was detected by real-time fluorescent quantitative PCR, the changes of TNF-α, IL-1β, and IFN-α in brain by enzyme-linked immunosorbent assay(ELISA), NO content in brain with nitrate reduction method, and pathological changes by hematoxylin-eosin(HE) staining. The result showed that the life extension rate in the high-dose, medium-dose, and low-dose FFE groups was 27.93%, 19.94%, and 10.66%, respectively, and the difference between the high-dose group and the model group was statistically significant(P<0.05). FFE decreased the viral load in brains of HSE mice. The levels of TNF-α, IL-1β, and IFN-α in ACV group and high-dose and medium-dose FFE groups were lower than those in the model group(P<0.01,P<0.05), and NO content in the three FFE groups was lower than that in the model group(P<0.01). In conclusion, FFE can improve the survival rate of HSE mice, reduce the load of herpes simplex virus type Ⅰ(HSV-1) in the brains of HSE mice, decrease the levels of inflammatory factors and NO content, and alleviate inflammation and pathological damage, thereby protecting the central nervous system.