小鼠异位气管移植模型中核转录因子NF—κB激活MCP-1诱导闭塞性细支气管炎的研究

目的利用同种异体小鼠异位气管移植模型,研究NF—κB是否激活MCP-1基因参与闭塞性细支气管炎（OB）,探讨OB的发病机制。方法将小鼠异位气管移植模型分成同基因组（BALB／C→BALB／C）和异基因组（BALB／C→C57BL／6）,在术后7、14、21d观察气管移植物是否发生OB;免疫组化染色检测气管移植物MCP-1蛋白表达;EMSA测定各组气管移植物NF—κB的转录活性改变;RT—PCR检测MCP-1的mRNA水平;ELASA检测外周血MCP-1蛋白水平。结果异基因移植实验组气管移植物管腔闭塞率在术后7d仅（6±3）％,14d为（28±）8％,21d达到（74±12）％,而同基因移植对照组管腔闭塞率在术后7～21d均小于3％;与对照组比较,实验组气管移植物NF—κB的转录活性在术后7、14、21d均明显升高;气管移植物MCP-1mRNA及血清中MCP-1蛋白水平术后7、14d升高,术后21d与对照组比较无显著差异。结论同种异体小鼠异位气管移植中,NF—κB转录活性增强,在移植后早期激活其下游靶基因MCP-1募集单核细胞和淋巴细胞攻击移植物,促进闭塞性细支气管炎的发生发展。     

beta cell cytoprotective strategies: establishing the relative roles for iNOS and ROS

Cytokine-induced beta cell destruction may be mediated by the generation of nitric oxide and/or reactive oxygen species. The relative importance of NO and ROS in cytokine-induced beta cell pathophysiology remains unclear. This investigation evaluates and contrasts the cytoprotective potential of antioxidant gene transfer, versus NF-kappaB inhibition, using a degradation-resistant mutant of IkappaBalpha. NF-kappaB inhibition conferred significant protection against cytokine-induced damage whereas antioxidant overexpression failed to provide protection. Conferred cytoprotection was associated with a suppression of iNOS activation and nitrite accumulation. Our data implicates iNOS, as opposed to ROS, as the pivotal player in cytokine-induced beta cell damage. From a therapeutic standpoint, strategies aimed at targeting the activation of iNOS may harbor therapeutic potential in preserving beta cell survival in the face of proinflammatory cytokine exposure.     

Intravenous administration of mannosylated cationic liposome/NFkappaB decoy complexes effectively prevent LPS-induced cytokine production in a murine liver failure model

The purpose of this study was to inhibit endotoxin induced cytokines production and liver injury by liver non-parenchymal cell (NPC) selective delivery of nuclear factor kappaB (NFkappaB) decoy using mannosylated cationic liposomes (Man-liposomes). In this study, we examined the distribution, inhibitory effect on cytokines production and ALT/AST of intravenously injected Man-liposome/NFkappaB decoy complex. Man-liposome/[(32)P] NFkappaB decoy complexes mostly accumulated in the liver, preferentially in NPC. In a murine lipopolysaccharide-induced liver failure model, the production of tumor necrosis factor-alpha (TNFalpha), IFNgamma, IL1-beta, ALT and AST were effectively reduced by Man-liposome complexes. However, cationic or galactosylated cationic liposome complexes could not inhibit TNFalpha production.