亚抑菌浓度山奈酚对鼠伤寒沙门氏菌侵袭鸡肠道上皮细胞的抑制作用研究

Inhibition effect of kaempferol on the invasion of Salmonella typhimurium to chicken intestinal epithelium cells at subinhibitory concenctions

为研究亚抑菌浓度山奈酚对鼠伤寒沙门氏菌(S.typhimurium)侵袭鸡肠道上皮细胞的作用,本研究首先通过二倍稀释法确定山奈酚的最小抑菌浓度(MIC)及其亚抑菌浓度,然后利用亚抑菌浓度山奈酚处理S.typhimurium后检测其SPI-1毒力基因表达水平及其对鸡肠道上皮细胞的侵袭变化规律和对雏鸡的致病性。结果显示,山奈酚对S.typhimurium CVCC542和SL1344株的MIC均>200μg/m L。亚抑菌浓度山奈酚能显著抑制S.typhimurium SPI-1毒力基因sip A、sop B、sop E2、hil A、hil C和hil D的基因表达,并显著降低S.typhimurium对鸡肠道上皮细胞侵袭数目,抑制S.typhimurium诱导鸡肠道上皮细胞乳酸脱氢酶(LDH)活性升高和F-actin骨架重排,并延长雏鸡存活时间。上述结果表明,亚抑菌浓度山奈酚能够抑制S.typhimurium侵袭鸡肠道上皮细胞,并降低其对雏鸡的致病性,为山奈酚应用于防治S.typhimurium感染提供了实验依据。

To study the effect of subinhibitory concenctions of kaempferol on the invasion of S.typhimurium to chicken intestinal epithelium ceils （CIEC）, the minimal inhibitory concentration （MIC） and subinhibitory concenctions of kaempferol against S. typhimurium were detected by double dilution method, and the mRNA levels of SPI-1 virulence genes of S. typhimurium in the presence of subinhibitory concenctions of kaempferol were detected. Then CIEC were infected with S. typhimurium in the presence of subinhibitory concenctions of kaempferol to detect the virulence of S.typhimunum in vitro. Finally, the pathogenicity of kaempferol-treated S. typhimurium was determined in chicken. These results showed both the MIC of kaempferol against S.typhimurium CVCC542 and SL1344 was 〉200 μg/mL. Subinhibitory concentrations of kaempferol repressed the mRNA expression of sipA, sopB, sopE2, hiIA, hiIC and hilD involved in SPI-1 and invasion of S.typhimurium on CIEC with no effect on the survival of S.typhimurium. In addition, subinhibitory concentrations of kaempferol inhibited F-actin cytoskeletal rearrangement and the activity of lactate dehydrogenase （LDH） caused by S.typhimtuSum. Moreover, subinhibitory concentrations of kaempferol prolonged the survival time of chickens challenged with S.typhimurium. These results suggested subinhibitory concentrations of kaempferol repressed the invasion of S. typhimurium to CIEC and the pathogenicity of S. typhimurium to chicken, which supported kaempferol as a promising agent for the prevention of S.typhimtuqum infection.