sábado, 20 de marzo de 2010

Intoxication and Burn Injury

Heme oxygenase-1 (HO-1) has been demonstrated to protect against
tissue injury. Furthermore, HO-1 is also shown to be
antioxidant. Our recent findings indicate that acute alcohol (EtOH)
intoxication exacerbates postburn intestinal and lung tissue
damage, and this was found to be neutrophil dependent. Because
neutrophil-mediated tissue injury involves the release of su-
peroxide anions (O2
), the present study examined the role of HO-1 in neutrophil O2
production following EtOH and burn injury.
Furthermore, we investigated whether HO-1 antioxidant properties are
mediated via modulation of p47phox
and/or p67phox
teins. Male rats ( 250 g) were gavaged with EtOH to achieve a blood
EtOH level of 100 mg/dL before burn or sham injury
( 12.5%total body surface area). Some rats were treated with HO-1
activator cobalt protoporphyrin IX chloride (Copp; 25 mg/kg
body weight) at the time of injury. On day 1 after injury, we found
that EtOH combined with burn injury significantly increased
neutrophil O2
production and p47phox
and p67phox
activation and decreased caspase-3 activity and apoptosis. This was accom-
panied with a decrease in neutrophil HO-1 levels. The treatment of
animals with HO-1 activator Copp normalized neutrophil
HO-1, O2
, p47phox
, and p67phox
following EtOH and burn injury. The expression of caspase-3, however,
was further decreased
in Copp-treated sham and EtOH plus burn groups. Moreover, Copp
treatment also prevented the increase in intestinal edema and
permeability following EtOH and burn injury. Altogether, these findings
provide a new insight into the mechanism by which HO-1
regulates neutrophil O2
production and protect the intestine from damage following EtOH and
burn injury. The Journal of
Immunology, 2008, 180: 6933–6940.
Multiple organ dysfunction and failure (MOD/MOF)
the leading cause of death in trauma, burn, and inten-
sive care unit patients (1–6). Many laboratory and
clinical studies have indicated that intestine plays a critical role in
the development ofMOD/MOF (7–9). An estimated 1 million burn
injuries are reported every year within the United States, and
nearly half of them occur under the influence of alcohol (EtOH) (7,
10–14). Studies have shown that patients who are intoxicated at
the time of injury are more susceptible to infection and have higher
incidence of mortality compared with burn patients who have not
consumed EtOH at time of injury (7, 10–15). Similarly, findings
from experimental studies have also shown that EtOH intoxication
before burn injury exacerbates the suppression of host immune
defense, impairs intestinal barrier function, and increases bacterial
Materials and Methods
Animals and reagents
Male Sprague-Dawley rats (225–250 g) were obtained from Charles River
Laboratories. Cobalt protoporphyrin IX chloride (Copp) was obtained from
Frontier Scientific. Anti-HO-1 Ab was obtained from StressGen Biotech-
nologies. Anti-p47phox
Ab and anti-p67phox
Abs were obtained from Up-
state Biotechnology. Anti-cleaved caspase-3 Ab was obtained from Cell
Signaling Technology.
Neutrophil O2
There was no significant difference in O2
production of neutro-
phils without PMA stimulation in any group (Fig. 1). The addition
of PMA resulted in an increase in neutrophil O2
production in all
four experimental groups. Neutrophil O2
production was mea-
sured with or without their stimulation with PMA (500 ng/ml) by
using cytochrome c reduction assay continuously at 550 nm for 60
min. The maximum rate of O2
production was calculated as de-
scribed in Materials and Methods. As shown in Fig. 1A, a peak
elevation in O2
was achieved within 20–25 min after the stimu-
lation of neutrophils with PMA. The values obtained at 20-min
time point were plotted in bar graph shown in Fig. 1B. Although
neutrophils from rats receiving EtOH or burn injury alone also
showed a tendency of an increase in their ability to produce O2
Hecho por: Willson A Mendoza C
FUENTE: http://www.jimmunol.org/cgi/reprint/180/10/6933.pdf

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