Jun C D, Pae H O, Kim Y C, Jeong S J, Yoo J C, Lee E J, Choi B M, Chae S W, Park R K, Chung H T
Department of Microbiology and Immunology, Wonkwang University School of Medicine and Medicinal Resources, Research Center of Wonkwang University, Chonbuk, South Korea.
J Ethnopharmacol. 1998 Sep;62(2):129-35. doi: 10.1016/s0378-8741(98)00063-4.
Since there is increasing evidence that nitric oxide (NO) plays a crucial role in the pathogenesis of inflammatory diseases, this study was undertaken to address whether the methanol (MeOH) extract and its fractions of the bark of Ulmus davidiana Planch (Ulmaceae) could modulate the expression of inducible NO synthase (iNOS) in thioglycollate-elicited murine peritoneal macrophages and murine macrophage cell line, RAW264.7 cells. Stimulation of the peritoneal macrophages and RAW264.7 cells with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS) resulted in increased production of NO in the medium. However, the butanol (BuOH) fraction of the MeOH extract of U. davidiana barks showed marked inhibition of NO synthesis in a dose-dependent manner. The inhibition of NO synthesis was reflected in the decreased amount of iNOS protein, as determined by Western blotting. The BuOH fraction did not affect the viability of RAW264.7 cells, as assessed by methylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide (MTT) assay; rather, it reduced endogenous NO-induced apoptotic cell death via inhibition of NO synthesis in RAW264.7 cells. On the other hand, the BuOH fraction showed no inhibitory effect on the synthesis of NO by RAW264.7 cells, when iNOS was already expressed by the stimulation with IFN-gamma and LPS. Collectively, these results demonstrate that the BuOH fraction inhibits NO synthesis by inhibition of the induction of iNOS in murine macrophages.
由于越来越多的证据表明一氧化氮（NO）在炎症性疾病的发病机制中起关键作用，因此开展了本研究，以探讨毛榆（榆科）树皮的甲醇（MeOH）提取物及其馏分是否能调节巯基乙酸诱导的小鼠腹腔巨噬细胞和小鼠巨噬细胞系RAW264.7细胞中诱导型一氧化氮合酶（iNOS）的表达。用干扰素-γ（IFN-γ）和脂多糖（LPS）刺激腹腔巨噬细胞和RAW264.7细胞，导致培养基中NO的产生增加。然而，毛榆树皮MeOH提取物的丁醇（BuOH）馏分以剂量依赖的方式显著抑制NO合成。通过蛋白质免疫印迹法测定，NO合成的抑制反映在iNOS蛋白量的减少上。通过噻唑蓝（MTT）法评估，BuOH馏分不影响RAW264.7细胞的活力；相反，它通过抑制RAW264.7细胞中的NO合成来减少内源性NO诱导的凋亡细胞死亡。另一方面，当通过IFN-γ和LPS刺激使iNOS已经表达时，BuOH馏分对RAW264.7细胞合成NO没有抑制作用。总的来说，这些结果表明BuOH馏分通过抑制小鼠巨噬细胞中iNOS的诱导来抑制NO合成。
