Michał Przemysław Pruchniak

Glucocorticoids can modulate the febrile response to

an injection of endotoxin.

Cytokines such as Interleukin-1, Interleukin-6 and

Tumor Necrosis Factor cause the release of

glucocorticoids from adrenal cortex.

Concentration of IL-6 and TNF in plasma is rising after

injection of lipopolysaccharide.

Nevertheless the role that play these cytokines in

modulating the febrile response are not completly

understood.

Injection of doses of TNF results in fever but there are

some evidences that endogenously produced TNF
lowers body temperature.

Hypothesis that IL-6 is a endogenous pyrogen.

Glucocorticoids inhibit the in vitro production of IL-6

and TNF but it is unclear to what extent it regulates the
in vivo production of these cytokines.

Experimental Animals

Adrenalectomized rats (ADX)

Shame-ADX rats

Normal rats (control)

Temperature Measurement

Body temperature was monitored using

surgically

implanted transmitter into peritoneal

cavity with was

connected with the Dataquest III

system. Implantation

was made 7 days before

experiments.

Intracerebroventricular Cannulas

The RU 38486 (20mg/kg) was added by the

cannula

implanted into the third ventricle of a

brain. At the end of experiments, the locations of the

cannula tracks

were histologically verifield.

Lypopolysaccharide

The LPS was obtained from E. Coli endotoxin

(Sigma lot no. 97F-4089).

Corticosterone replacement peelets

25, 50, 100 mg and placebo peelets purchased

from Innovative Research.

The puropse: Test that the hypothesis that LPS injection
would lead to increased level of TNF-like and IL-6-like
activities and higher fevers in ADX rats compared to shame-
AXD rats.

1)

The body temperarature of 7 AXD and 5 shame AXD rats

with were injected with 50 g/kg LPS were mesure at 5 min.

intervals for 24 hours.

2)

Other group of 12 AXD and 12 shame-AXD rats were used

to colect plasma for cytokines assay. The half of them were
injected with 50g/kg LPS and the rest with saline. One hour

postinjection three animals from each group were killed and
the rest after 4 hours. The blood was collected for assays.

1)

Injection of LPS led to higer fever in the ADX group
than in shame AXD.

2)

IL-6 activity were not signficantly different 1h post
LPS injection but after 4h were higher in ADX than
shame-ADX.

3)

Activity of TNF were the same after 1 and 4 hours in
both groups

4)

Injection of saline has not influence at concentration
of IL-6 and TNF in ADX and shame-ADX rats.

The pourpose: Test that exposure to an open field would
result in higher circulating levels of IL-6-like activityand
higher fevers in ADX rats compared with shame-ADX rats.

1)

13 ADX rats and 11 shame-ADX rats were exposed to

an open field to induce psychological stress. Open field
was a big cage with fluorescent lights suspended from
the celling.

2)

After 30 minuts of exposure the temperature were

messured and next animals were killd and their blood
was collected for assays.

1)

Exposure to an open field induced in higher fever in
the ADX-rats than in shame-ADX

2)

Also the activity of IL-6 were higher in ADX group

The pourpose: Test the hypothesis that administering
the glucocorticoid antagonist RU 38486 to rats before
injecting them with LPS would result in higher levels of
IL-6-like activity and fever simmilar to that observed in
ADX rats.

1)

6 rats were given 20mg/kg RU 38486 with corn oil, 6

rats were given corn oil and 6 rats were given saline.

2)

21 rats were given 20mg/kg RU 38486 and 21 rats

were given corn oil. Afer temperature returned to
normal stage animals were injected with 50g/g LPS

and body temperature were mesure at 5-min. intervals.

1)

Administering of RU in corn oil, corn oil or saline did
not cause changes in body temperature.

2)

After LPS injection there were 2 rises in body
temperature. At the RU group the body temperature
were higher in both rises.

3)

The RU animals have higher amount of IL-6 in
serum than animals treated with corn oil.

The purpose: Test the hypothesis that administering RU
to rats before exposing them to an open field stress
would result in higher circulating levels of IL-6-like
activity and similar fever to ADX rats.

1)

5 rats were admininostered 20mg/kg RU with corn oil

and 5 wih only corn oil.

2)

Afer body temp. levels off animals were exposed to

an open field for 30 min. Body temperature was
monitored and blood were collected for assays.

1)

After exposure to an open field RU rats developed
higher temperature than corn-oil rats

2)

IL-6 activity also were higher at RU rats

The purpose: test the hypothesis that administering RU
intracerebroventriculary to rats before injecting them
with LPS would result in higher circulating levels of IL-6-
like activity and higher temperature.

1)

6 rats were injected intracerebroventriculary with RU

suspended in 2%ethanol-saline, 6 rats were injected
intracerebroventriculary only with 2%ethanol-saline

2)

All animals were next injected with LPS and body

temperature were mesured

1)

Body temperature were higher in RU treated rats
before and after LPS injection

2)

Concentration of IL-6 were the same in both groups

The purpose: test the hypothesis that ADX animals given
a replacement dose of corticosterone, with mimics
plasma concentration observed in stressed and
nonstressed animals, would develop fevers similar to
those observed in shame-ADX rats given placebo pellets.

1)

AXD rats were given with placebo pellets, 100, 50, 25

mg corticosterone pellets and shame-ADX rats were
given only placebo pellets

2)

After 7 days animals were exposured to an open field

for 30 minuts. After 24h animals were injected with LPS
and next exposured to stress situation and killed.

I.

There were evidences that glucocorticoids
modulate the febrile response and this experiment
show that not only LPS-induced fever is higher in
ADX rats, but also plasma concentration of IL-6 is
increased.

II.

Open field stress causes rise in body temperature
that have similarities to LPS-induced fever and ADX
rats develop higher temperature than shame-ADX.
The plasma IL-6 activity of ADX rats were also
higher than shame-ADX.

III.

Using orally glicocorticoids antagonist RU 38486
increased body temperature in response to LPS and
open field stress. IL-6 concentration was also
increased.

IV.

Intracerebrovntricular injection of RU led to increased
body temp in response to LPS. However the IL-6
concentration was the same (It is possible that
examination group was to small).

V.

The data from sixth protocol sugest that elevated
level of glicocorticosteron is needed to supress fever.