阿司匹林对炎症条件下人血管内皮细胞一氧化氮的产生及诱导型一氧化氮合酶mRNA表达的影响

Effects of aspirin on production of nitric oxide and inducible nitric oxide synthase mRNA expression under inflammatory conditions in human vascular endothelial cells

目的 :探讨炎症时阿司匹林 (AS)对内皮细胞一氧化氮 (NO)的产生及诱导型一氧化氮合酶 (iNOS)基因表达的抑制作用。方法 :Griess法测上清液NO-2 /NO-3 水平、黄递酶法测NOS活性、常规生化法测乳酸脱氢酶(LDH)、丙二醛 (MDA)浓度 ,染料排除法测细胞活力 ,RT -PCR技术分析iNOSmRNA水平。结果 :白介素 (IL) - 1β、肿瘤坏死因子 (TNF) -α、γ -干扰素 (INF)联用脂多糖 (LPS)诱导后上清液中NO-2 /NO-3 由 (4 2 7± 0 75 ) μmol/L增加到(9 35± 1 2 5 ) μmol/L ,对内皮细胞造成明显的损伤。但 3mmol/LAS组NO生成及NOS活性明显降低 ,LDH释放率及MDA浓度下降 ,细胞存活率上升 ,与NO诱导组相比差异显著。并随AS剂量的增加对NO的抑制及对细胞的保护作用更加明显 ,但AS对生理水平的NO没有抑制作用。同时发现 10mmol/L浓度以下AS对iNOSmRNA表达水平没有影响 ;但 10 - 2 0mmol/L的AS则可在转录水平上抑制iNOSmRNA的表达。并观察到水杨酸钠及消炎痛不具有抑制NO产生的作用。结论 :AS具有明显抑制IL - 1β、TNF -α、γ -INF及LPS诱导NO生成的作用 ,从而保护血管内皮细胞避免炎症时高浓度NO的损伤。

AIM: To explore the effect of aspirin on inducible nitric oxide synthesis and gene expression under inflammation in endothelial cells. METHODS: Using NADPH, Griess methods and RT-PCR, the activity of isozymes of NO synthase (NOS), nitric oxide (NO) level, and iNOS mRNA expression were examined respectively. Also, the lactate dehydrogenase (LDH) release rate, malondialdehyde (MDA) content and cell viability were measured. RESULTS: Aspirin (3 mmol/L) reduced inducible NO production and NOS activity(P<0.05), caused a significant decrease in LDH release rate and MDA content with a further increase in cell viability. Aspirin inhibited inducible NO excretion and alleviated the damage caused by NO in a concentration-dependent manner. However,aspirin had no effect on basal NO levels in the absence of stimulation by inflammatory factor. On the other hand, under middle concentration (<10 mmol/L), aspirin was able to reduce enzymatic activity of NOS and protein expression by increasing the stability of iNOS mRNA. In contrast, at high concentration (20 mol/L), aspirin could decrease the stability of iNOSmRNA. Sodium salicylate and indomethacin did not inhibit inducible NO production. CONCLUSION: Aspirin could significantly inhibit inducible NO production in vascular endothelial cells during inflammation.