Objective To investigate the influence of quercetin on Caspase-3 of lung epithelial tumour A549 infected with H1N1. Methods MTT method was adopted to determine H1N1 virulence, quercetin cytotoxicity, inhibitory effect of quercetin on A549 cytopathic with H1N1 cause. H1N1 of 100 TCID50 was used to infect A549 for 2 h and then change quercetin fluid containing 10 mg/L to cultivate. After 4, 12, 24, 48 h, cells were collected to extract total protein. By adopting the Western-blot method and applying Image-Pro Plus, the grayscale value of Caspase-3 and fl-actin were determined. The gray ratio was relative expression quantity of Caspase-3. Results The TCIDso of H1N1 to A549 was IO-4175, the highest non-toxic concentration of quercetin to A549 (Tco) was 40 mg/L, the least effective concentration (MEC) of quercetin inhibition to A549 cytopathic with H1N1 cause was 10 mg/L. After the infection of H1N1, quercetin significantly inhibited Caspase-3 expression within 4-48 h, showing that quercetin plays an obvious antiapoptotic role. Conclusion Quercetin can play antiviral infectious functions by inhibiting the content or activity of Caspase-3.%目的 观察银杏叶主要活性成分槲皮素对甲型H1N1流感病毒感染的人肺上皮瘤细胞A549凋亡效应酶Caspase-3的影响.方法 采用MTT法测定H1N1毒力、槲皮素细胞毒性作用、槲皮素对H1N1致A549细胞病变的抑制作用.然后用100 TCID50甲型H1N1感染A549 2 h后换用含10 mg/L槲皮素维持液继续培养,于感染后4、12、24、48 h收集细胞,提取细胞总蛋白,采用Western blot方法,应用Image-Pro Plus测定Caspase-3与β-actin灰度值,两者灰度比值为Caspase-3的相对表达量.结果 甲型H1N1 A549的TCID50为10-4.75,槲皮素A549的最大无毒浓度为40 mg/L,槲皮素抑制甲型H1N1致A549细胞病变的最小有效浓度为10 mg/L.在甲型H1N1感染A549细胞后4～ 48 h内,槲皮素可显著抑制Caspase-3蛋白表达,具有明显的抗凋亡作用.结论 槲皮素可通过抑制Caspase-3含量或活性而发挥抗病毒感染作用.
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