Supression of the expression of cyclooxygenase-2 by ozonides of oleate ester

据报道，臭氧化橄榄油具有抗炎作用。然而，臭氧化橄榄油的化学结构细节及其作用机制长期以来一直不清楚。我们最近证明了臭氧化橄榄油的主要成分是三油酸甘油酯的三臭氧化物。在这项研究中，我们确定了臭氧化橄榄油的几个次要成分，包括低分子量和高分子量的“交叉臭氧”。此外，为了阐明臭氧化橄榄油的抗炎作用机制，我们研究了臭氧化橄榄油和油酸甲酯臭氧化物对脂多糖（LPS）刺激的巨噬细胞样THP-1细胞产生PGE_2和表达环氧化酶考克斯-2的影响。橄榄油、油酸甲酯及其臭氧化物在一定浓度范围内不影响细胞活力和形态。橄榄油本身不影响LPS诱导的巨噬细胞样THP-1细胞中考克斯-2表达和PGE_2生成。然而，臭氧化橄榄油抑制这两个反应的浓度依赖性的方式。油酸甲酯臭氧氧化物也抑制考克斯-2表达和PGE_2生成，而油酸和油酸甲酯没有这种抑制作用。臭氧化橄榄油和油酸甲酯臭氧化物的这种作用被证明是由于它们对I B磷酸化的抑制作用，而I B磷酸化是LPS刺激的巨噬细胞中核因子-κ B（NF B）活化和随后的考克斯-2基因转录所必需的。除臭氧化物环外不含其它官能团的臭氧化物也有抑制作用。此外，臭氧化橄榄油和油酸甲酯臭氧化物对参与AP-1活化的p38和JNK的磷酸化没有影响。这些结果表明臭氧化橄榄油和油酸甲酯臭氧化物通过抑制lкBαNFкB途径抑制考克斯-2基因转录，从而抑制LPS诱导的巨噬细胞样THP-1细胞PGE_2的产生。

Ozonized olive oil has been reported to exert anti-inflammatory effect. However, the details of chemical structure of ozonized olive oil and its action mechanism have long been unclear. We have recently demonstrated that the major component of the ozonized olive oil is triozonide of triolein. In this study, we identified several minor components of ozonized olive oil, including "cross ozonides" of low and high molecular weight. In addition, to elucidate the anti-inflammatory action mechanism of ozonized olive oil, we investigated the effects of ozonized olive oil and methyl oleate ozonides on the generation of PGE_2 and the expression of Cyclooxygenase-2 (COX-2) in Lipopolysaccharide (LPS)-stimulated macrophage-like THP-1 cells. Olive oil, methyl oleate and their ozonides did not affect cell viability and morphology within a concentration used. LPS-induced COX-2 expression and PGE_2 generation in macrophage-like THP-1 cells were not affected by olive oil itself. However, ozonized olive oil inhibited both reactions in a concentration-dependent manner. Methyl oleate ozonides also inhibited COX-2 expression and PGE_2 generation whereas oleic acid and methyl oleate did not show such inhibitory effects. Such actions of ozonized olive oil and methyl oleate ozonide were shown to be due to their inhibitory effect on lкB phosphorylation which is required for Nuclear factor-kappa B (NFкB) activation and subsequent COX-2 gene transcription in LPS-stimulated macrophages. The inhibitory effect was also observed with ozonide having no functional group except for ozonide ring. In addition, ozonized olive oil and methyl oleate ozonide showed no effect on the phosphorylations of p38 and JNK, which are involved in the activation of AP-1. These results demonstrate that ozonized olive oil and methyl oleate ozonides suppress LPS-induced PGE_2 generation in macrophage-like THP-1 cells through inhibition of COX-2 gene transcription by suppressing the lкBαNFкB pathway.