大蒜多糖体外抑制呼吸道合胞病毒作用及其机制

Inhibitory Effect of Garlic Polysaccharide on Respiratory Syncytial Virus in Vitro and Its Mechanism

目的研究大蒜多糖体外抗呼吸道合胞病毒(RSV)活性,并初步探讨其作用机制。方法采用MTT法测定大蒜多糖对HEp-2细胞毒性。研究不同浓度的大蒜多糖对RSV复制周期不同阶段的影响,用MTT法检测药物对RSV的病毒抑制率,以病毒抑制率和治疗指数(TI)评价药效。通过实时荧光定量RT-PCR检测大蒜多糖对RSV基因表达的影响。采用酶联免疫吸附法(ELISA)检测大蒜多糖对RSV感染诱导细胞表达的IL-6和IL-8的影响。结果大蒜多糖对HEp-2细胞最大无毒浓度(TC0)为50. 3μg/mL,半数毒性浓度(TC50)为116. 8μg/mL。大蒜多糖可有效抑制RSV生物合成(TI=3. 34),且与阳性对照药物(利巴韦林)抑制效果相当。大蒜多糖可显著抑制RSV病毒L、P基因表达(P <0. 05),并显著下调RSV病毒感染诱导的IL-6和IL-8表达(P <0. 05)。结论大蒜多糖可能是通过抑制与RSV毒复制晚期相关的L、P基因表达而有效抑制RSV复制,且能在一定程度上下调病毒诱导的炎症因子表达。

Objective To investigate the inhibitory effect of garlic polysaccharide （GP） on respiratory syncytial virus in vitro and its mechanism. Methods The cytotoxicity of GP on HEp-2 cells was determined by MTT assay. The inhibitory effects of GP on different stages of RSV replication cycle were studied. The virus inhibition rate of RSV was detected by MTT assay, and the drug efficacy was evaluated by virus inhibition rate and therapeutic index （TI）. The effects of GP on the expression of RSV gene and the levels of IL-6 and IL-8 were detected by real-time quantitative PCR and ELISA, respectively. Results The maximum non-toxic concentration （TC0） of GP to HEp-2 cells was 50.3 μg/mL,and the half toxicity concentration （TC50） was 116.8 μg/mL. GP effectively inhibited thebiosynthesis of RSV, and its effect was similar to positive control drug （ribavirin）. In addition, GP significantly inhibited the expression of RSV L and P genes （ P 〈 0.05 ）, down-regulated the high expression of IL-6 and IL-8 induced by RSV infection （ P 〈 0.05 ）. Conclusion GP may inhibit RSV replication by decreasing the expression of RSV L and P genes.