[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.