Lindenblatt N, Bordel R, Schareck W, Menger M D, Vollmar B
Department of Experimental Surgery, University of Rostock, Rostock, Germany.
Arterioscler Thromb Vasc Biol. 2004 Mar;24(3):601-6. doi: 10.1161/01.ATV.0000118279.74056.8a. Epub 2004 Jan 22.
By heme degradation, heme oxygenase-1 (HO-1) provides endogenous carbon monoxide and bilirubin, both of which play major roles in vascular biology. The current study aimed to examine whether induction of HO-1 and its byproducts modulate the process of microvascular thrombus formation in vivo.
In individual microvessels of mouse cremaster muscle preparations, ferric chloride-induced thrombus formation was analyzed using intravital fluorescence microscopy. When mice were pretreated with an intraperitoneal injection of hemin, a HO-1 inducer, immunohistochemistry and Western blot protein analysis of cremaster muscle tissue displayed a marked induction of HO-1. In these animals, superfusion with ferric chloride solution induced arteriolar and venular thrombus formation, which, however, was significantly delayed when compared with thrombus formation in animals without HO-1 induction. The delay in thrombus formation in hemin-treated mice was completely blunted by tin protoporphyrin-IX, a HO-1 inhibitor, but not by copper protoporphyrin-IX, which does not inhibit the enzyme. Coadministration of the vitamin E analogue Trolox in HO-1-blocked animals almost completely restored the delay in thrombus formation, implying that, besides CO, the antioxidant HO pathway metabolite bilirubin mainly contributes to the antithrombotic property of HO-1. This was further supported by the fact that bilirubin was found as effective as hemin in delay of ferric chloride-induced thrombus formation. Animals with HO-1 induction revealed reduced P-selectin protein expression in cremaster muscle tissue, which most probably presented the molecular basis for delayed thrombus growth.
Local induction of HO-1 activity may be of preventive and therapeutic value for clinical disorders with increased risk of thrombotic events.
通过血红素降解，血红素加氧酶-1（HO-1）可产生内源性一氧化碳和胆红素，二者在血管生物学中均发挥重要作用。本研究旨在探讨诱导HO-1及其产物是否能调节体内微血管血栓形成过程。
在小鼠提睾肌制备物的单个微血管中，采用活体荧光显微镜分析氯化铁诱导的血栓形成。当小鼠腹腔注射HO-1诱导剂血红素进行预处理后，提睾肌组织的免疫组织化学和蛋白质印迹分析显示HO-1明显被诱导。在这些动物中，用氯化铁溶液灌注可诱导小动脉和小静脉血栓形成，然而，与未诱导HO-1的动物相比，血栓形成明显延迟。HO-1抑制剂锡原卟啉-IX可完全消除血红素处理小鼠的血栓形成延迟，但不抑制该酶的铜原卟啉-IX则无此作用。在HO-1被阻断的动物中联合给予维生素E类似物生育三烯酚几乎完全恢复了血栓形成的延迟，这意味着除一氧化碳外，抗氧化剂HO途径代谢产物胆红素主要促成了HO-1的抗血栓特性。胆红素在延迟氯化铁诱导的血栓形成方面与血红素效果相当这一事实进一步支持了这一点。诱导HO-1的动物提睾肌组织中P-选择素蛋白表达降低，这很可能是血栓生长延迟的分子基础。
局部诱导HO-1活性对于血栓形成风险增加的临床疾病可能具有预防和治疗价值。
