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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 the inhibitory effect of lactate dehydrogenase (Lactobacillus acidophilus) on the nuclear, transcription and cyclooxygenase-2 (COX-2) transcription of NF-κB p65 induced by endotoxin (LPS). Methods Rat intestinal mucosal microvascular endothelial cells (RIMMVECs) were cultured in vitro. The control group, LPS group, LA preconditioning group and PDTC (specific inhibitor of NF-κB) Pretreatment group 4 experimental groups. After treated with LPS for 30min, NF-κB p65 protein level in nucleus and cytoplasm of different experimental groups was detected by Western blotting. After LPS treated for 9h, the levels of NF-κB p65 and COX-2 mRNA were detected by real-time fluorescence quantitative PCR. Results The total amount of NF-κB p65 protein in the experimental groups was not significantly different after 30 min of LPS treatment, but the ratio of NF-κB p65 in LA and PDTC pretreatment groups was significantly lower than that in LPS group. After LPS treatment for 9 h, The levels of NF-κB p65 and COX-2 mRNA in the treated group were significantly lower than those in the LPS group. Conclusion Lactic acid has a similar function as NF-κB blocker, and can inhibit LPS-mediated nuclear transcription of NF-κB p65, and inhibit the transcription of target genes such as COX-2 downstream of NF-κB, thereby exerting anti-inflammatory effects.