Maitra Subir R, Bhaduri Sikha, El-Maghrabi M Raafat, Shapiro Marc J
Department of Emergency Medicine, School of Medicine, Stony Brook University Hospital, Stony Brook, NY 11794-7400, USA.
Acad Emerg Med. 2005 Sep;12(9):797-803. doi: 10.1197/j.aem.2005.04.017.
Hemorrhage initiates an inflammatory response that induces the systemic release of cytokines and sequestration of polymorphonuclear neutrophils. Sequestered polymorphonuclear neutrophils release proteases, including matrix metalloproteinases (MMPs) that degrade elements of the extracellular matrix, contributing to the morbidity and mortality seen from hemorrhage. Activation of MMPs may be associated with changes in transforming growth factor beta1 (TGF-beta1) and caspase-3 signaling pathways. In this study, the authors examined hemorrhage-induced changes in the expression of rat hepatic MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-l), TGF-beta1, and caspase-3 activities in the presence and absence of the MMP inhibitor hydroxamate.
Hemorrhagic shock was induced in fasted, anesthetized, and cannulated rats by rapid phlebotomy to a mean arterial pressure level of 40 mm Hg, maintained for 90 minutes by withdrawal and infusion of blood, followed by a resuscitation period of lactated Ringer's infusion. Rats received either hydroxamate (25 mg/kg) or vehicle by gavage before hemorrhage. Twenty-four hours after resuscitation, plasma and liver samples were collected. Liver MMP-9, TGF-beta1, and caspase-3 levels were quantified by Western immunoblotting. Plasma glutamic oxaloacetic transaminase (GOT) and plasma glutamic pyruvic transaminase (GPT) were determined enzymatically.
Plasma GOT, plasma GPT, and liver MMP-9, TGF-beta1, and caspase-3 levels were all significantly elevated at 24 hours postresuscitation when compared with the control values. Hepatic TIMP-1, an in vivo inhibitor of MMP-9, was unaltered at 24 hours. Hydroxamate treatment reduced GOT, GPT, MMP-9, TGF-beta1, and caspase-3 levels at 24 hours. The mortality of hemorrhaged untreated rats was 29% after 24 hours, and pretreatment with hydroxamate reduced mortality to 0%.
These results indicate the beneficial effects of MMP inhibitor in preventing an increase in GOT, GPT, MMP-9, TGF-beta1, and caspase-3 activity with the potential for improvement of hepatic injury due to hemorrhage.
出血引发炎症反应，诱导细胞因子的全身释放和多形核中性粒细胞的隔离。被隔离的多形核中性粒细胞释放蛋白酶，包括降解细胞外基质成分的基质金属蛋白酶（MMPs），这会导致出血相关的发病率和死亡率。MMPs的激活可能与转化生长因子β1（TGF-β1）和半胱天冬酶-3信号通路的变化有关。在本研究中，作者研究了在存在和不存在MMP抑制剂异羟肟酸的情况下，出血诱导的大鼠肝脏MMP-9、金属蛋白酶组织抑制剂-1（TIMP-1）、TGF-β1表达变化以及半胱天冬酶-3活性。
对禁食、麻醉并插管的大鼠通过快速放血诱导出血性休克，使平均动脉压达到40 mmHg水平，通过抽血和输血维持90分钟，随后进行乳酸林格氏液输注复苏期。大鼠在出血前通过灌胃接受异羟肟酸（25 mg/kg）或赋形剂。复苏24小时后，收集血浆和肝脏样本。通过Western免疫印迹法定量肝脏MMP-9、TGF-β1和半胱天冬酶-3水平。通过酶法测定血浆谷草转氨酶（GOT）和血浆谷丙转氨酶（GPT）。
与对照值相比，复苏后24小时血浆GOT、血浆GPT以及肝脏MMP-9、TGF-β1和半胱天冬酶-3水平均显著升高。肝脏TIMP-1作为MMP-9的体内抑制剂，在24小时时未发生改变。异羟肟酸处理降低了24小时时的GOT、GPT、MMP-9、TGF-β1和半胱天冬酶-3水平。未治疗的出血大鼠24小时后的死亡率为29%，而异羟肟酸预处理将死亡率降至0%。
这些结果表明MMP抑制剂在预防GOT、GPT、MMP-9、TGF-β1和半胱天冬酶-3活性增加方面具有有益作用，有可能改善出血引起的肝损伤。
