烫伤合并金葡菌感染大鼠组织CD14 mRNA的改变

目的　探讨细菌脂多糖受体CD14在烫伤合并金黄色葡萄球菌 (金葡菌 )感染中的变化规律及其意义。　方法　采用大鼠 2 0 %总体表面积Ⅲ度烫伤合并金葡菌攻击造成脓毒症模型 ,动态检测心、肝、肺、肾等重要器官中CD14mRNA表达的改变 ,同时观察内毒素在动物循环及主要脏器内的分布特点。　结果　烫伤合并金葡菌脓毒症早期 ,各脏器内毒素含量即明显高于正常对照组 ,并于2～ 6h达峰值 ,其中以肝、肺组织内毒素水平升高幅度最为显著 (P <0 .0 5 )。而血浆内毒素水平亦于伤后 2h显著高于正常对照组 (分别为 0 .30 5 6EU/ml和 0 .12 5 0EU/ml,P <0 .0 5 )。与此同时 ,小肠组织中二胺氧化酶的活性明显降低 (P <0 .0 5 )。烫伤合并金葡菌感染后 ,各组织CD14mRNA的表达亦呈不同程度升高 (P <0 .0 5 ) ,其中肺脏改变尤为显著 ,伤后 6、2 4h肺脏CD14mRNA表达分别为正常对照组的 1.80和 1.81倍。　结论　烫伤合并金葡菌攻击可导致内毒素移位和组织CD14mR NA表达不同程度升高 ,CD14基因表达的上调可能与移位内毒素的刺激作用有关。

The change in CD14 mRNA expression in rats with scald injury and Staphylococcus aureus challenge

OBJECTIVE: To investigate the potential role and changes in CD14 in postburn Staphylococcus aureus sepsis. METHODS: Wistar rats were subjected to a 20% total body surface area (TBSA) full-thickness thermal injury and followed by Staphylococcus aureus challenge. Plasma and tissue samples from liver, kidneys, lungs and heart were collected to determine endotoxin (lipopolysaccharide, LPS) levels and CD14 mRNA expression. RESULTS: It was found that after thermal injury combined with Staphylococcus aureus sepsis, LPS levels in various tissues were markedly increased, peaking at 2 approximately 6 h (P < 0.05), then returned to baseline at 24 h. Plasma LPS level was also increased significantly at 2hrs after Staphylococcus aureus challenge compared with that in normal control animals (0.3056 EU/ml vs. 0.1250 EU/ml, P < 0.05). In addition, the intestinal diamine oxidase (DAO) activity decreased (P < 0.05). This indicated that the integrity of intestinal mucosa was damaged. Meanwhile, tissue CD14 mRNA expressions were up-regulated in all tissues (P < 0.05), especially in lungs. CONCLUSION: These data suggested that gut-originated LPS translocation and CD14 mRNA expression could be induced by thermal injury with Staphylococcus aureus sepsis. The up-regulation of CD14 gene expression might be associated with the local endotoxin activation secondary to postburn sepsis.