目的 探讨嗜酸乳杆菌代谢产物乳酸(LA）对内毒素（LPS）介导的NF-κB p65入核、转录及环氧化酶-2（COX-2）转录的抑制作用。方法 以体外培养的大鼠肠黏膜微血管内皮细胞（RIMMVECs）为材料，设对照组、LPS组、LA预处理组和NF-κB特异性阻断剂吡咯烷二硫代氨基甲酸盐（PDTC）预处理组4个实验组。LPS作用30min后，Western blotting 检测不同实验组细胞核、细胞质内NF-κB p65蛋白水平，LPS作用9h后，实时荧光定量PCR法检测NF-κB p65、COX-2 mRNA水平。结果 LPS作用30min后，各实验组细胞NF-κB p65蛋白总量差异不显著，但LA和PDTC预处理组细胞核内NF-κB p65比例显著低于LPS组；LPS作用9h后，LA和PDTC预处理组细胞NF-κB p65和COX-2 mRNA水平显著低于LPS组。结论 乳酸具有类似NF-κB阻断剂的作用，可以抑制LPS介导的NF-κB p65入核、转录，抑制NF-κB下游靶基因如COX-2的转录，从而发挥抗炎作用。

Objective To investigate whether lactic acid(LA),which was extracted from the culture supernatant of Lactobacillus,could inhibit lipopolysaccharide(LPS)-induced translocation of NF-κB p65 from cytoplasm to nucleus and transcription of NF-κB p65 and cyclooxygenase 2(COX-2). Methods Rat intestinal mucosa microvascular endothelial cells(RIMMVEs) were cultured in vitro and were divided into 4 groups:control group,LPS group,LA pretreated group and NF-κB inhibitor (pyrrolidinecarbodithioate,PDTC) pretreated group.The protein of NF-κB p65 in cytoplasm and in nucleus was detected by Western blotting analysis after RIMMVEs were treated with LPS for 30 minutes.The mRNA of NF-κB p65 and COX-2 was detected by real time quantity-PCR after RIMMVEs were treated with LPS for 9 hours. Results In a short time(treated with LPS for 30 minutes),the protein expression of NF-κB p65 had no notable difference but the ratios of p65 in nuclei of LA and PDTC pretreated group were notably lower than that of LPS group.After a longer time(treated with LPS for 9 hours),the mRNA expression of NF-κB p65 and COX-2 were notably lower than LPS group. Conclusion LA has the effects like NF-κB inhibitor,notably inhibiting LPS-induced translocation of NF-κB p65 from cytoplasm to nucleus and transcription of NF-κB p65 and COX-2.By this way,LA inhibits inflammatory response.