中文摘要：

目的：研究板蓝根活性提取物体外抗呼吸道合胞病毒（RSV）的作用。方法：MTT法检测人喉癌上皮细胞（hep-2）中板蓝根活性提取物对RSV的抑制作用。荧光定量RT-PCR检测药物对RSV非结构蛋白NS1和L蛋白RNA合成的影响。结果：MTT结果显示药物治疗组和预防组在0.25~1 mg/m L浓度时均表现出抑制RSV的作用,其中0.5 mg/m L药物对RSV的抑制率分别是34.2%和52.2%,药物没有显示出直接杀伤和抑制RSV的效应。荧光定量RT-PCR检测表明药物作用1 h,RSV的NS1和L的RNA水平均显著低于病毒组（P〈0.05）。结论：RSV感染hep-2过程中,板蓝根活性提取物具有预防和早期抗病毒复制的效应,但未显示出直接杀伤RSV的功能。

英文摘要：

Objective ： To study the effect of active extracts from radix isatidis against RSV （ respiratory syncytial virus） in vitro. Methods ： We observed the anti - RSV ability of the extracts from radix isatidis in human larynx carcinoma epithelial ceils （ hep - 2） by MrIT method. In order to explore the antiviral mechanism of radix isatidis extracts, RNA synthesis of nonstructural 1 （NS1） protein and L protein in RSV were detected by real - time fluorescent quantitative RT - PCR. Results ： Our study showed that in the concentration of 0.25,0.5,1 mg/mL, radix isatidis extracts had obvious anti - RSV effect in hep - 2 cells for both drug therapy group and preventive treatment group. Especially in the concentration of 0.5 mg/mL, extracts showed distinct antiviral efficacy in drug therapy group with 34.2% viral inhibition rate and in drug preventive group with 52.2% viral inhibition rate. When the drug and RSV were mixed together directly at 4℃ for 2 hours,no obvious antiviral effect was found in the present study. 1 hour after the drug was used on the RSV - infected cells, the result of real - time fluorescent quantitative RT - PCR indicated that RNA level of NS1 and L of RSV in drug treatment group were significantly lower than those in virus group （ P 〈 0. 05 ）. Conclusion ： Our study indicated that active extracts from radix isatidis played a preventive role on hep - 2 in the course of RSV infection. The drug could also inhibit replication of RSV at the early stage, but did not show the effect of directly killing RSV.