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目的:探讨葡萄糖调节蛋白78(GRP78)在大鼠肝肺综合征发病中的作用及其与肠源性内毒素血症的关系。方法:Wistar大鼠被随机分为4周组、6周组和8周组3个时点,采用复合致病因素法制备大鼠肝硬化合并肝肺综合征(HPS)模型,并设标准饮食的正常大鼠作为对照组。采用HE染色观察肺组织病理变化;测定血浆中丙氨酸氨基转移酶(ALT)、内毒素、TNF-α和肺组织匀浆中的TNF-α、丙二醛(MDA)的含量。Western blotting和RT-PCR法检测肺组织标本中GRP78蛋白和mRNA表达水平。结果:模型组动物血浆内毒素含量随病程进展逐渐增高;肺组织中GRP78蛋白和mRNA的表达随HPS进展逐步增高,且各时点间的表达有显著差异(P<0.05);血浆内毒素与升高的GRP78蛋白水平间呈高度正相关(P<0.01)。血浆ALT和TNF-α含量以及肺组织匀浆中TNF-α和MDA含量随病程进展逐渐增高;血浆内毒素含量以及肺组织中GRP78蛋白分别与血浆TNF-α和肺组织中TNF-α、MDA的含量呈高度正相关(P<0.01)。在各时点,模型组动物血浆TNF-α含量、肺组织匀浆TNF-α、GRP78蛋白及mRNA均显著高于正常对照组(P<0.05)。在第6周和第8周,模型组动物血浆内毒素和ALT的含量以及肺组织匀浆中MDA的含量均显著高于正常对照组(P<0.05)。结论:肝硬化时形成的肠源性内毒素血症作为内质网应激的重要应激原,通过氧化应激激活肺组织的内质网应激反应导致GRP78表达增高,很可能是HPS发病的重要机制。
Objective: To investigate the role of glucose regulatory protein 78 (GRP78) in the pathogenesis of hepatopulmonary syndrome in rats and its relationship with enterogenous endotoxemia. Methods: Wistar rats were randomly divided into 4 weeks group, 6 weeks group and 8 weeks group at 3 time points. The compound pathogenic factors were used to prepare the rat models of cirrhosis and hepatopulmonary syndrome (HPS), and a standard diet Of normal rats as control group. The pathological changes of lung tissue were observed by HE staining. The contents of alanine aminotransferase (ALT), endotoxin, TNF-α and lung homogenate were measured. The expression of GRP78 protein and mRNA in lung tissue were detected by Western blotting and RT-PCR. Results: The level of plasma endotoxin in model group increased gradually with the progression of the disease. The expression of GRP78 protein and mRNA in lung tissue increased gradually with the progress of HPS, and the expression of GRP78 in lung tissue was significantly different (P <0.05) Elevated GRP78 protein levels were highly positive correlation (P <0.01). The contents of ALT and TNF-α in plasma and TNF-α and MDA in lung homogenate gradually increased with the course of disease progression. The levels of plasma endotoxin and GRP78 protein in lung tissue were positively correlated with TNF-α and TNF-α, MDA (P <0.01). At each time point, the content of TNF-α in plasma, TNF-α, GRP78 protein and mRNA in lung homogenate of model group were significantly higher than those of normal control group (P <0.05). At the 6th week and the 8th week, the contents of plasma endotoxin and ALT in the model group and the contents of MDA in the lung homogenate were significantly higher than those in the normal control group (P <0.05). CONCLUSIONS: Intestinal endotoxemia, which is formed during cirrhosis of the liver, acts as an important stressor of endoplasmic reticulum stress. Endoplasmic reticulum stress-induced activation of lung tissue by oxidative stress leads to increased expression of GRP78, which is likely to be the cause of HPS The important mechanism.