抑制核因子-κB减轻腹主动脉瘤破裂所致多脏器损伤的实验研究

目的研究抑制核因子-κB(NF-κB)激活对大鼠破裂腹主动脉瘤(RAAA)模型多脏器损伤的影响。方法Wistar大鼠45只,随机分为假手术组、实验组和吡咯烷二硫代氨基甲酸酯(PDTC)组(每组15只)。实验组和PDTC组均通过大鼠模型模拟腹主动脉瘤破裂的病理生理过程包括失血性休克期1h、腹主动脉阻断45min、再灌注2h。实验组和PDTC组在失血休克期分别静脉给予生理盐水或PDTC50mg/kg。取肺、小肠组织,观察组织形态学改变,测定肺组织湿/干重比、髓过氧化物酶(MPO)及小肠微循环血流量的变化。逆转录多聚酶链反应检测肺、小肠NF-κB p65和细胞间黏附分子(ICAM)-1的mRNA表达,免疫组织化学和Western印迹检测NF-κB p65、ICAM-1的蛋白产物表达。结果实验组中,肺PMN计数(39个±8个)/HP,湿/干重比(7.6±1.2),与假手术组(11个±3个/HP,3.3±0.8)比较差异均有统计学意义(P<0.01);小肠微循环血流量显著减少与假手术组(0.71ml.min-1.g-1±0.11ml.min-1.g-1)比较差异有统计学意义(P<0.01);实验组肺及小肠NF-κB p65和ICAM-1的mRNA及蛋白产物表达均明显增强;应用PDTC干预后,小肠微循环血流量(0.64ml.min-1.g-1±0.06ml.min-1.g-1)与实验组比较差异均有统计学意义(P<0.01)。结论抑制NF-κB激活可以减轻大鼠RAAA模型多脏器功能损伤,其作用机制可能是通过抑制ICAM-1基因及其蛋白产物的表达,减少中性粒细胞的作用而实现的。

Inhibition of nuclear factor kappa B attenuates multiple organ injury following ruptured abdominal aortic aneurysm: an experiment with rats

OBJECTIVE: To investigate the effect of inhibition of nuclear factor kappa B on multiple organ injury following ruptured abdominal aortic aneurysm. METHODS: Forty-five Wistar rats underwent catheterization to observe the intestinal microcirculation blood flow, and were randomly divided into 3 equal groups. Rats of the ruptured abdominal aortic aneurysm (RAAA) group underwent laparotomy and extraction of blood to cause hemorrhage shock for 1 h (hemorrhagic shock phase), by the end of this phase normal saline at the dose of 50 ml/kg was injected intravenously, after that the abdominal aorta and bilateral common iliac arteries were blocked with artery clamps for 45 min so as to cause lower torso ischemia, and then the extracted blood was reperfused. The lungs, small intestine were taken out to undergo histological examination, and examination of lung polymorphonuclear neutrophilic leukocyte (PMN) sequestration, lung wet tissues/dry (W/D) tissues ratio, and myeloperoxidase (MPO) activity. The rats of pyrrolidine dithiocarbamate (PDTC) group were perfused with PDTC, a specific inhibitor of nuclear factor kappa B (NF-kappaB), by the end of the hemorrhagic shock phase. And the rats of the sham operation group were perfused of normal saline. RT-PCR was used to detect the mRNA expression of NF-kappaB p65 and intercellular adhesion molecule (ICAM). Western blotting was used to detect the protein expression of NF-kappaB p65 and ICAM-1. Immunohistochemistry was used to detect the expression of NF-kappaB p65 and ICAM-1 in the lung and small intestine tissues. RESULTS: Histological examination showed that severe damage could be found in the lung and small intestine of the RAAA group, and damages were significantly mild in the PDTC group. Lung PMN sequestration, W/D ratio, MPO activity were significantly increased in the RAAA group and these changes were relatively mild in the PDTC group (all P < 0.01). The intestinal microcirculation blood flow was 0.25 +/- 0.04 mlxmin(-1)xg(-1) in the RAAA group, significantly less than that of the sham operation group (0.71 +/- 0.11 mlxmin(-1)xg(-1), P < 0.01), and was 0.64 +/- 0.06 mlxmin(-1)xg(-1) in the PDTC group, significantly higher than that of the RAAA group (P < 0.01). The mRNA expression of NF-kappaB p65 in the lung of the RAAA group was 0.68 +/- 0.22, significantly higher than that of the sham operation group (0.11 +/- 0.02, P < 0.01) and that of the PDTC group (0.23 +/- 0.07, P < 0.01). The mRNA expression of NF-kappaB p65 in the intestine of the RAAA group was 0.48 +/- 0.10, significantly higher than that of the sham operation group (< 0.20 +/- 0.05, P < 0.01) and that of the PDTC group (0.27 +/- 0.06, P < 0.01). The mRNA expression of ICAM-1 in the lung of the RAAA group was 0.92 +/- 0.31, significantly higher than that of the sham operation group (0.07 +/- 0.02, P < 0.01) and that of the PDTC group (0.21 +/- 0.04, P < 0.01). The mRNA expression of ICAM-1 in the intestine of the RAAA group was 0.74 +/- 0.15, significantly higher than that of the sham operation group (0.14 +/- 0.05, P < 0.01) and that of the PDTC group (0.25 +/- 0.08, P < 0.01). The protein expression of NF-kappaB p65 in the lung of the RAAA group was 1.04 +/- 0.26, significantly higher than that of the PDTC group (0.52 +/- 0.13, P < 0.01). The protein expression of NF-kappaB p65 in the intestine of the RAAA group was 1.20 +/- 0.30, significantly higher than that of the PDTC group (0.64 +/- 0.21, P < 0.01). The protein expression of ICAM-1 in the lung of the RAAA group was 0.40 +/- 0.12, significantly higher than that of the PDTC group (0.18 +/- 0.06, P < 0.01). The protein expression of ICAM-1 in the intestine of the RAAA group was 0.46 +/- 0.15, significantly higher than that of the PDTC group (0.22 +/- 0.05, P < 0.01). Immunohistochemistry showed that NF-kappaB p65 and ICAM-1 positive cells were widely distributed in the lungs and intestine of the RAAA group and were rarely distributed in the sham operation group. CONCLUSION: PDTC attenuates the multi-organ injury by inhibiting the expression of NF-kappaB p65, thus reducing the mRNA and protein expression of its downstream gene ICAM-1 gene.