Department of Pharmacology, Xi'an Jiaotong University School of Medicine, PR China.
Life Sci. 2011 May 9;88(19-20):839-45. doi: 10.1016/j.lfs.2011.03.003. Epub 2011 Mar 31.
Atherosclerosis is a chronic inflammatory response of the arterial wall to multiple endothelial injuries. As one of the inflammatory markers, fibrinogen has been implicated in pathogenesis of atherosclerosis. But, it is not completely understood whether atherogenesis of fibrinogen is related to its pro-inflammatory effect on vascular smooth muscle cells (VSMCs). The purpose of the present study was to observe effects of fibrinogen and fibrin degradation products (FDP) on interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and inducible nitric oxide synthase (iNOS) generation in rat VSMCs.
Rat VSMCs were cultured, and fibrinogen and FDP were used as stimulants for IL-6, TNF-α, and iNOS. IL-6 and TNF-α level in the supernatant were measured by ELISA, mRNA expression of IL-6, TNF-α, and iNOS were assayed with RT-PCR, and protein expression of iNOS was detected with western blot and immunocytochemistry.
Fibrinogen and FDP both significantly stimulated mRNA and protein expressions of IL-6, TNF-α and iNOS in VSMCs in time- and concentration-dependent ways. The pro-inflammatory potency of FDP is higher than fibrinogen, which seems to mean that smaller fragments of the protein have greater pro-inflammatory activity. Fibrinogen and FDP promote more protein expressions of IL-6 and TNF-α compared to iNOS, suggesting that fibrinogen and FDP produce a pro-inflammatory effect on VSMCs mainly by IL-6 and TNF-α.
These findings are helpful to better understand pro-inflammatory effect of fibrinogen on VSMCs involved in atherogenesis, and imply a therapeutic strategy targeting hyperfibrinogenemia in atherosclerosis.
动脉粥样硬化是动脉壁对多种内皮损伤的慢性炎症反应。纤维蛋白原作为炎症标志物之一，已被认为与动脉粥样硬化的发病机制有关。但是，纤维蛋白原的动脉粥样硬化形成是否与其对血管平滑肌细胞（VSMCs）的促炎作用有关，目前还不完全清楚。本研究旨在观察纤维蛋白原和纤维蛋白降解产物（FDP）对大鼠 VSMCs 白细胞介素 6（IL-6）、肿瘤坏死因子-α（TNF-α）和诱导型一氧化氮合酶（iNOS）生成的影响。
培养大鼠 VSMCs，用纤维蛋白原和 FDP 作为刺激物，检测 IL-6、TNF-α 和 iNOS 的生成。ELISA 法检测上清液中 IL-6 和 TNF-α 的水平，RT-PCR 法检测 IL-6、TNF-α 和 iNOS 的 mRNA 表达，Western blot 和免疫细胞化学法检测 iNOS 的蛋白表达。
纤维蛋白原和 FDP 均能显著地以时间和浓度依赖的方式刺激 VSMCs 中 IL-6、TNF-α 和 iNOS 的 mRNA 和蛋白表达。FDP 的促炎作用强于纤维蛋白原，这似乎意味着该蛋白的较小片段具有更强的促炎活性。纤维蛋白原和 FDP 促进 IL-6 和 TNF-α 的蛋白表达多于 iNOS，提示纤维蛋白原和 FDP 主要通过 IL-6 和 TNF-α 对 VSMCs 产生促炎作用。
这些发现有助于更好地理解纤维蛋白原对参与动脉粥样硬化形成的 VSMCs 的促炎作用，并暗示了针对动脉粥样硬化中高纤维蛋白原血症的治疗策略。
