核因子-κB激活与一氧化氮合酶mRNA表达在重症急性胰腺炎肺损伤中的作用

Role of intrapulmonary expression of inducible nitric oxide synthas gene and nuclear factor-κB activation in severe pancreatitis-associated lung injury

目的:探讨重症急性胰腺炎(SAP)大鼠肺组织核因子-κB(NF-κB)活化及诱导型一氧化氮合酶mRNA表达与肺损伤的关系。方法:SD大鼠随机分为对照组、SAP组、二硫代氨基甲酸吡咯烷(PDTC)预处理组。建立各组模型后取肺组织行病理学观察,免疫组织化学法观察NF-κB的表达,实时荧光定量PCR法检测iNOS mRNA表达。结果:对照组仅极少量NF-κB活化,iNOS mRNA呈低水平表达。SAP组NF-κB表达明显增加,并呈动态变化,6h达高峰,主要表达于中性粒细胞、单核/巨噬细胞、支气管黏膜上皮细胞、肺泡上皮细胞的胞质和胞核内,iNOSmRNA表达明显上调。PDTC预处理组NF-κB表达明显减少,iNOS mRNA表达亦下调,但仍高于对照组。结论:SAP时肺组织NF-κB活化并通过调控iNOS mR-NA的表达参与肺损伤。PDTC可能通过抑制NF-κB活性进而下调iNOS mRNA的表达,减轻肺损伤。

Ojective： To explore the relationship of intrapulmonary activation of nuclear factor-kB （NF-kB） and the expres- sion of inducible nitric oxide synthase （iNOS） mRNA with pulmonary injury in rats with severe acute pancreatitis （SAP）. Methods： SD rats were randomly divided into a control group, a SAP group and a pyrrolidine dithiocarbamate （PDTC） pretreated group. SAP was induced by retrograde injection of 5% sodium taurocholate into the bile-pancreatic duct （0.1 ml/100 g）. Histological changes of lungs were observed after hematoxylin-eosin （HE） staining. Activation of NF-kB in pulmonary tissues was detected by immunohistochemical methods. The intrapulmonary expression of iNOS mRNA was assayed by fluo- rescent quantitive reverse transcription polymerase chain reaction （FQ-RT-PCR）. Results： A little positive signals were ob- served and the expression level of iNOS mRNA was very low in the control group. The expression level of NF-kB in the SAP group was obviously higher compared with the control group. The number of positive cells reached its peak at 6 h. The posi tire signals were mostly observed in the cytoplasm and nuclei of neutrophils, macrophages, bronchial epithelial cells and alveolar epthelial cells. The expression of iNOS mRNA greatly increased in the SAP group. The number of positive cells decreased obviously in PDTC pretreated groups. The expression of iNOS mRNA in PDTC groups was significantly weaker than that in the SAP group, but still significantly higher than that in the control group （P〈 0. 05）. Conclusion： The activation of NF-kB may be involved in the SAP lung injury through regulating the expression of iNOS mRNA. PDTC might inhibit the activation of NF-kB and then reduce the expression of iNOS mRNA and effectively alleviate the severity of lung injury.