葡萄糖调节蛋白78在大鼠肝肺综合征肺微血管重构中的作用

 目的：探讨葡萄糖调节蛋白78(GRP78)引发大鼠肝肺综合征（HPS）肺微血管重构的机制。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HPS模型，并设标准饮食的正常大鼠作为对照组。免疫组化染色法观察肺组织GRP78、Ⅷ因子相关抗原(FⅧ-RAg)C/EBP 同源蛋白(CHOP)/生长阻滞及DNA损伤诱导蛋白153(GADD153)、caspase-12、Bcl-2和核因子(nuclear factor,NF)-κB的表达。RT-PCR和Western blotting法检测肺组织血管内皮生长因子(VEGF) mRNA和蛋白表达水平。结果：模型组动物肺组织中GRP78、FⅧ-RAg及VEGF蛋白的表达随HPS进展逐步增高，CHOP/GADD153及caspase-12的表达随HPS进展逐步降低，Bcl-2和NF-κB随病程进展表达逐渐增加，NF-κB尤以胞核表达增高明显。GRP78与FⅧ-RAg及VEGF蛋白水平呈明显正相关(P<0.01)，而与CHOP/GADD153及caspase-12的表达呈明显负相关(P<0.01)。在各时点，模型组动物肺组织GRP78和FⅧ-RAg显著高于正常对照组；VEGF蛋白和mRNA均显著高于正常对照组；而CHOP/GADD153及caspase-12 的表达均低于正常对照组(P<0.05)。结论：GRP78可能通过促进血管内皮细胞增殖和抑制其凋亡，促进肺微血管重构，导致HPS的发病。

Role of glucose-regulated protein 78 in pulmonary microvascular remodeling during development of rat hepatopulmonary syndrome

AIM：To explore the mechanisms of pulmonary microvascular remodeling induced by glucose-regulated protein 78 (GRP78) in the development of hepatopulmonary syndrome (HPS) in rats. METHODS：The Wistar rats were randomly divided into HPS groups at the 4th, 6th and 8th weeks, and normal control groups at the corresponding time points. The rat model of HPS produced in the process of liver cirrhosis was induced by employing multiple pathogenic factors to the animals. The rats in normal control group were designed by feeding with standard diet and mineral water. The expression of GRP78, factor Ⅷ- related antigen (FⅧ-RAg), C/EBP homologous protein (CHOP, also called growth arrest and DNA damage-inducible protein 153, GADD153), caspase-12, Bcl-2 and nuclear factor (NF)-κB in the lung tissues were measured by immunohistochemistry. The expression of VEGF at mRNA and protein levels in the lungs was measured by the methods of RT-PCR and Western blotting, respectively. RESULTS：The expression of GRP78, FⅧ-RAg,VEGF and Bcl-2 proteins was gradually increased with the HPS development. The protein expression of NF-κB was also gradually increased, especially in nucleus. GRP78 protein in the lung was positively correlated with the expression of FⅧ-RAg and VEGF, but negatively correlated with the expression of CHOP/GADD153 and caspase-12. The protein levels of GRP78 and FⅧ-RAg, and VEGF at both mRNA and protein levels were higher, and the protein levels of CHOP/GADD153 and caspase-12 were lower in the rats with HPS at every time point than those in normal control rats (P<0.05). CONCLUSION：Overexpression of GRP78 in the lung may be the critical pathogenesis of HPS by promoting cell survival and proliferation, and inhibiting cell apoptosis, thus leading to pulmonary microvascular remodeling.