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Stress may make it easier for germs to
infect skin wounds as researchers below proved.
Investigators created skin wounds in
mice that were exposed to stressful living conditions. The
researchers then applied Streptococcus bacteria to the wounds,
and compared the healing rates of the stressed mice with those
of mice with skin wounds that were also exposed to the bacteria
but did not undergo the same levels of stress.
Mice that had been stressed out prior
to wounding and infection showed a 30%
delay in wound healing at 3 and 5 days compared
with the mice that were not stressed, the report indicates.
In addition, the investigators found
that after 5 days, the stressed mice had 100,000
times more opportunistic bacteria in their wounds
than the non-stressed mice.
Seven days after the bacteria exposure,
about 85% of the wounds in the stressed mice were infected,
versus about 27% of the wounds in the non-stressed mice.
In this study, stress
increased the rate of wound infection by threefold.
Stress disrupts the body's equilibrium, in turn significantly
impairing its ability to control and eradicate bacterial infection
during wound healing.
The bottom line is that stress shuts
down either the recruitment or the function of those immune
cells needed to fight infection.
Research in humans has found that psychological
stress can take a toll on the immune system by
reducing the concentration of cytokines, proteins that help
to ward off infections. In one study, skin wounds on the arms
of women who had higher levels of the stress hormone cortisol
had lower levels of key compounds released by the body to
mediate healing.
Brain,
Behavior, and Immunity online 2001;10.1006
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