Lo C J, Chiu K C, Fu M, Lo R, Helton S
Department of Surgery, University of California, Los Angeles, California, 90095, USA.
J Surg Res. 1999 Apr;82(2):216-21. doi: 10.1006/jsre.1998.5524.
Fish oil-supplemented diets have anti-inflammatory and immunomodulating effects, though the exact mechanism(s) are unknown. This study investigated the effects of eicosapentanenoic acid (EPA), a major component of fish oil, on transcriptional regulation of tumor necrosis factor (TNF) gene in lipopolysaccharide (LPS)-stimulated macrophages (MO).
RAW 264.7 cells, a mouse MO cell line, were grown in EPA-rich media for 24-48 h. MO were washed and exposed to Escherichia coli LPS (1 microg/ml) for 2 h. TNF mRNA expression was measured by Northern blot assays. Total nuclear extracts were harvested for the measurement of NF kappa B with electrophoretic mobility shift assays. Supershift assays were performed with anti-P50 or anti-P65 antibodies to show components of NF kappa B dimers. TNF production was determined by L929 bioassays.
LPS stimulated RAW cell TNF mRNA expression and NF kappa B activity. In contrast, RAW cells grown in EPA-rich media had less TNF mRNA expression and an altered composition of the NF kappa B subunits (P65/P50 dimers) in the presence of LPS. TNF production by LPS-stimulated MO was reduced by EPA.
The inhibitory effect of EPA on LPS-stimulated MO TNF gene transcription and protein elaboration is, in part, mediated through altering NF kappa B activation by reducing the P65/P50 dimers.
补充鱼油的饮食具有抗炎和免疫调节作用，但其确切机制尚不清楚。本研究调查了鱼油的主要成分二十碳五烯酸（EPA）对脂多糖（LPS）刺激的巨噬细胞（MO）中肿瘤坏死因子（TNF）基因转录调控的影响。
将小鼠MO细胞系RAW 264.7细胞在富含EPA的培养基中培养24 - 48小时。洗涤MO细胞并使其暴露于大肠杆菌LPS（1微克/毫升）2小时。通过Northern印迹分析测量TNF mRNA表达。收集总核提取物，用电泳迁移率变动分析测量NF-κB。用抗P50或抗P65抗体进行超迁移分析以显示NF-κB二聚体的成分。通过L929生物测定法测定TNF产生。
LPS刺激RAW细胞TNF mRNA表达和NF-κB活性。相反，在富含EPA的培养基中生长的RAW细胞在存在LPS的情况下TNF mRNA表达较少，且NF-κB亚基（P65/P50二聚体）的组成发生改变。EPA降低了LPS刺激的MO产生的TNF。
EPA对LPS刺激的MO TNF基因转录和蛋白质合成的抑制作用部分是通过减少P65/P50二聚体来改变NF-κB激活介导的。
