D. Altavilla et al., Oxidative stress causes nuclear Factor-kappa B activation in acute hypovolemic hemorrhagic shock, FREE RAD B, 30(10), 2001, pp. 1055-1066
Nuclear Factor kappaB (NF kappaB) is an ubiquitous rapid response transcrip
tion factor involved in inflammatory reactions and exerts its action by exp
ressing cytokines, chemokines, and cell adhesion molecules. We investigated
the role of NF-kappaB in acute hypovolemic hemorrhagic (Hem) shock. Hem sh
ock was induced in male anesthetized rats by intermittently withdrawing blo
od from an iliac catheter over a period of 20 min (bleeding period) until m
ean arterial blood pressure (MAP) fell and stabilized within the range of 2
0-30 mmHg, Hemorrhagic shocked rats died in 26.3 +/- 2.1 min following the
discontinuance of bleeding, experienced a marked hypotension (mean arterial
blood pressure = 20-30 mmHg) and had enhanced plasma levels of Tumor Necro
sis Factor-alpha (200 +/- 15 pg/ml, 20 min after the end of bleeding). Furt
hermore, aortas taken 20 min after bleeding from hemorrhagic shocked rats s
howed a marked hypo-reactivity to phenylephrine (PE; 1nM to 10 muM) compare
d with aortas harvested from sham shocked rats. Hem shocked rats also had i
ncreased levels of TNF-alpha mRNA in the liver (15-20 min after the end of
bleeding) and enhanced plasma levels of 2,5-dihydroxybenzoic acid (2,5-DHBA
, 6 +/- 2.2 mum), 2,3-dihydroxybenzoic acid (2,3-DHBA; 13 +/- 2.1 mum), bot
h studied to evaluate: OH. production. Electrophoretic mobility shift assay
showed that liver NF-kappaB binding activity increased in the nucleus 10 m
in after the end of hemorrhage and remained elevated until the death of ani
mals. Western blot analysis suggested that the levels of inhibitory I kappa
B alpha protein in the cytoplasm became decreased at 5 min after the end of
bleeding. IRFI-042, a vitamin E analogue (20 mg/kg intraperitoneally 2 min
after the end of bleeding), inhibited the loss of I kappaB alpha protein f
rom the cytoplasm and blunted the increase in NF-kappaB binding activity. F
urthermore IRFI-042 increased survival time (117.8 +/- 6.51 min; p <.01) an
d survival rate (vehicle = 0% and IRFI-042 = 80%, at 120 min after the end
of bleeding), reverted the marked hypotension, decreased liver mRNA for TNF
-<alpha>. reduced plasma TNF-alpha (21 +/- 4.3 pg/ml), and restored to cont
rol values the hypo-reactivity to PE. Our results suggest that acute blood
loss (50% of the estimated total blood volume over a period of 20 min) caus
es early activation of NF-kappaB, likely through an increased production of
reactive oxygen species. This experiment indicates that NF-kappaB-triggere
d inflammatory cascade becomes early activated during acute hemorrhage even
in the absence of resuscitation procedures. (C) 2001 Elsevier Science Inc.