THRO?+lBOSIS RESEARCH Printed in the United
EFFECT PLATELET
Vol. States
OF HYPERLIPIDEMIA AGGREGATION
AND STRESS
E.Bassenge,H.Schmid-SchBnbein
Department
of Physiology,
Received
17.3.1975; Accepted by by Executive
1975 Inc.
ON
IN RABBITS
I(. Oversohl,
(Received
7, pp.481-492, Pergamon Press,
University
of Munich, Munich
in revised form 9.6.1975. Editor N. Goossens. Editorial Office 5.8.1975)
ABSTRACT The effect of a high cholesterol diet on plasma lipids, platelet aggregation, vessel pathology and arterial blood pressure was studied in rabbits.In addition, the effect of stress (swimming or orthostasis) on these parameters was tested and compared with data obtained from control rabbits. The high cholesterol diet resulted in high plasma cholesterol and triglyceride levels and an elevated arterial blood pressure. Platelet aggregation (measured with a photometric procedure) was significantly enhanced in the hyperlipidemic state. An enhanced platelet aggregation was also noted in rabbits on standard diet during stress situations. Platelet aggregation was most pronounced when stress was applied in hyperlipidemic rabbits. coronary and Atheromatosis of the aorta, renal, femoral, carotid arteries was noted in rabbits on a high cholesterol diet. Strips of atheromatotic aortas revealed a significant decline in yield stress. The high cholesterol rabbits may represent a rein with producible model for induction of atheromatosis, platelet aggregation, hemodynamics, blood lipids and vascular pathology can be studied and correlated.
INTRODUCTION Recently several investigators have focussed on the role in the pathogenesis of atherosclerosis (1,2, 3,4,5,6,7,8,9). 481
of thrombocytes In rabbits,
STRESS,LIPmS,PLATELM:
482
atheromatosis
can be iniated
hanced
aggregation
in rabbits
by a cholesterin
In a certain
(10, 11,12,13).
and/or
has been
observed
taneously
as many
of these
in the hyperlipidemic
hypertension
as possible,
under
to cover
we have
observed this
simul-
investigated
:
of hyperlipidemia
structural
an en-
has been
In the attempt
aspects
a fewweeks
atherosclerosis,
arterial
(18,19).
rabbits
diet within
of thrombocytes
In humans,
condition
rich
to human
adhesion
(14,15,16,1’7).
1. The effect
analogy
Vo1.7,No.3
CLLJMPIXG
on platelet
aggregation
and vascular
changes.
2. The importance lipidemia
of physical
on platelet
3. The changes
stress
and stress
associated
with hyper-
aggregation.
in arterial
blood
pressure
and heart
rate
in the awake
animals. 4. These
data have particularly
suitability
of the rabbit
of platelet
function
The advent small several enhanced before
platelet
Since
stress
with respect
to the
analysis
of a possible
significance
of measuring
platelet
aggregation
monitoring
of platelet
function
clinical
aggregation
and during
lipidemic
the daily
(20,21).
for
analyzed
atherosclerosis.
technique
allowed
months
model
in human
of a novel
samples
been
under
studies stress
situations
was
in humans
(22,23),
studied
during
indicate
platelet
in normal
on very
an
aggregation and in hyper-
rabbits.
METHODS Over
a period
mean
2,68
In addition
formation. lipids
were 70 g/kg
Lage/Lippe,
8 and 16 weeks
blood
12 weeks
kg body weight)
(Altromin, added.
of at least
to this group,
for additional
A control
group
and thrombocyte
without
the addition
plasma
were
16 male
per day) to which 6 animals
histological of 12 male function,
every
(range
fed with a standard
of cholesterol.
determined
rabbits
were
week
2,0-3,2;
rabbits
2 70 of cholesterol sacrificed
after
was
5,
of atheroma
comparable
in age,
was fed with the standard
Cholesterol other
diet for
examination rabbits,
from
and triglyceride
in both groups
(24).
weight,
diet levels
in
STRESS,LIPIDS,PLATELET
To obtain lipid
blood
samples
concentration,
(Statham
for measurements
as well
P 37 transducer),
anesthesia
(25 mg/kg
The catheters
0,5
were
solution
(20001. U. /ml).
avoided
by careful
premeasured -1,5
ml of blood
The rabbits
from
venous
catheter.
obtained
To quantify
platelet
in this
was
with the
and by discarding determination. by swimming
stressed
position
the orthostatic
blood
box,
(head
test,
obtained
pressure
which
up) for
or swimming were
20 min
by orthostasis.
into a tight fitting
measurements
the
from
and heart
blood the
rate were
various
was employed
under
1:lO)
under
dark
(20,21),
field
which
illumination.
illuminates
platelet
conditions,
the sample
rich
plasma
a novel
involves
a rotating
The dark field (50 ~1) of titrated
(obtained
by centrifugation
4 min).
The method
measuring
the platelet
by Schmid-Schonbein approximately specimen
and femoral
arteries
were
technique).
Specimen
judgement
of the whole
aorta)
Immediately
following
load that lead
to the rupture
diet,
is extensively
from
the rabbits
the aorta,
the myocardium
haemalaun
considered
under
taken
and from
and were
aggregation,
(20).
3 months
Histological
tosis.
were
into the vertical
aggregation
rheoscope
% Na-Citrate,
arteries
vena cava.
with heparin
stressed
squeezed
of arterial
method
condenser
After
and superior
mg/kg
catheter.
“rheoscope”
described
were
aggregation
cone -plate
at 500 g for
diet were
and after
Tracings
microphotometric
(3.8
chemical
animals
0,Ol
of the catheter
withdrawn
Before
via aortic
ml)
solution
the horizontal
for platelet
(0,l
for each
under
with a heparin-dextran
of heparin-dextran
these
inserted
of the blood
filling
the rabbits
15 min repeated. samples
Contamination
Otherwise
this purpose
was lifted
and filled
and
recording
with fentanyl
into the aorta
with high cholesterol
in 21’ C water. For
daily
aggregation
pressure
were
premeditation
volumetric
volume
blood
catheters
mg/kg)
flushed
of platelet
continous
chronic
Nembutal,
and dehydrobenzperidol
first
as for
483
CLLNPIXG
of abdominal
were
were
coronary, (stained
aorta
renal,
(after
macroscopic
taken
at the origin
representative
for
the formation
of excised
strips
carotid
by Sudan III and
always
the sacrifice,
sacrificed.
we determined of abdominal
of the renal of atheroma-
the maximum aorta.
After
484
STRESS,LIPIDS,PLATELET
correction
for the cross
computed.
In five
animals,
studied
by scanning
(25,26)
and Malissa
animals
were
and fixed
(27).
studied
stress
microscopy,
metal
of high cholesterol
was aorta
by Hess
electronmicrographs
of tension
and heavy
(in dynes/cm2)
as described
The scanning
state
Vo1.7,No.3
of the abdominal
surface
with a Cambridge
with carbon
period
the yield
the inner
electron
in its existing
and coated months
section,
CLUMPING
et al.
of five
SEM.
The aorta
using
6 % glutaraldehyd
(AU).
In two animals
was followed
was
was excised
by three
solution a three
months
of normal
diet.
RESULTS Rabbits
on high cholesterol
plasma
cholesterol
levels
increase
In the control
significantly
218) were
pressure There
was
rate
month.
cholesterol Atheroma
atheromatosis period
these
7 mg%,
levels
did not
during
of observation.
mean
at rest
was
arterial
after
224+
blood
the observation rabbits
arterial
mean
In
blood
15 beat/min.
pressure period
arterial
eight weeks
or
of three blood
period
of
I).
observed
and carotid were
diet,
rabbits
in mean
during
arteries.
observed.
of high cholesterol
aorta
and Royle
was not only present
femoral
11 mg% and 56:
as high as 2550 mg% (mean
by 19 mmHg
by King
were
I. Control
levels
rate
in the abdominal
suggested
Atheromatosis
time
(table
in table
in
period
in the hyperlipidemic
formation
atheromas
rabbits
significantly
diet
to a scheme
renal,
increase
in the control
rose
and heart
with time
month
In the control
9Ot 4mmHg,
59:
on normal
the three
increase
as depicted
were
cholesterol
observed.
However,
pressure
large
rabbits
was no significant
heart
rabbits
during
a steady
levels
and triglycerides
the hyperlipidemic 1’704:
showed
and triglycerid
of cholesterol
respectively.
diet
was qilantified
(13).
accordmg
In hyperlipidemic
the pathological
in the abdominal In the control
The atheromatosis diet as demonstrated
rabbits
examination. aorta,
rabbits
coronary, no signs
correlated in Figure
of
with the I. The
STRESS,LIPmS,PUTELET
485
CLUXPDJG
TABLlZ. I Effect
of cholesterol
vascular
yield
rich
diet on lipid
normal rabbits n= 12
hemodynamics
Imean art. pressure mmHg
briglycerides
mg%
mg%
59211
56+7
90+4
1
hyperlipidemic I rabbits
and
stress
1 Cholesterol i
I
level,
heart Irate1 min
ield
stress
107dyn/cm2
224+ I,15 -
64+10 I
’ 1704+218+ -
1300+361+
109+6+ -
+ p
EFFECT PLATELET
Vol. States
OF HYPERLIPIDEMIA AGGREGATION
AND STRESS
E.Bassenge,H.Schmid-SchBnbein
Department
of Physiology,
Received
17.3.1975; Accepted by by Executive
1975 Inc.
ON
IN RABBITS
I(. Oversohl,
(Received
7, pp.481-492, Pergamon Press,
University
of Munich, Munich
in revised form 9.6.1975. Editor N. Goossens. Editorial Office 5.8.1975)
ABSTRACT The effect of a high cholesterol diet on plasma lipids, platelet aggregation, vessel pathology and arterial blood pressure was studied in rabbits.In addition, the effect of stress (swimming or orthostasis) on these parameters was tested and compared with data obtained from control rabbits. The high cholesterol diet resulted in high plasma cholesterol and triglyceride levels and an elevated arterial blood pressure. Platelet aggregation (measured with a photometric procedure) was significantly enhanced in the hyperlipidemic state. An enhanced platelet aggregation was also noted in rabbits on standard diet during stress situations. Platelet aggregation was most pronounced when stress was applied in hyperlipidemic rabbits. coronary and Atheromatosis of the aorta, renal, femoral, carotid arteries was noted in rabbits on a high cholesterol diet. Strips of atheromatotic aortas revealed a significant decline in yield stress. The high cholesterol rabbits may represent a rein with producible model for induction of atheromatosis, platelet aggregation, hemodynamics, blood lipids and vascular pathology can be studied and correlated.
INTRODUCTION Recently several investigators have focussed on the role in the pathogenesis of atherosclerosis (1,2, 3,4,5,6,7,8,9). 481
of thrombocytes In rabbits,
STRESS,LIPmS,PLATELM:
482
atheromatosis
can be iniated
hanced
aggregation
in rabbits
by a cholesterin
In a certain
(10, 11,12,13).
and/or
has been
observed
taneously
as many
of these
in the hyperlipidemic
hypertension
as possible,
under
to cover
we have
observed this
simul-
investigated
:
of hyperlipidemia
structural
an en-
has been
In the attempt
aspects
a fewweeks
atherosclerosis,
arterial
(18,19).
rabbits
diet within
of thrombocytes
In humans,
condition
rich
to human
adhesion
(14,15,16,1’7).
1. The effect
analogy
Vo1.7,No.3
CLLJMPIXG
on platelet
aggregation
and vascular
changes.
2. The importance lipidemia
of physical
on platelet
3. The changes
stress
and stress
associated
with hyper-
aggregation.
in arterial
blood
pressure
and heart
rate
in the awake
animals. 4. These
data have particularly
suitability
of the rabbit
of platelet
function
The advent small several enhanced before
platelet
Since
stress
with respect
to the
analysis
of a possible
significance
of measuring
platelet
aggregation
monitoring
of platelet
function
clinical
aggregation
and during
lipidemic
the daily
(20,21).
for
analyzed
atherosclerosis.
technique
allowed
months
model
in human
of a novel
samples
been
under
studies stress
situations
was
in humans
(22,23),
studied
during
indicate
platelet
in normal
on very
an
aggregation and in hyper-
rabbits.
METHODS Over
a period
mean
2,68
In addition
formation. lipids
were 70 g/kg
Lage/Lippe,
8 and 16 weeks
blood
12 weeks
kg body weight)
(Altromin, added.
of at least
to this group,
for additional
A control
group
and thrombocyte
without
the addition
plasma
were
16 male
per day) to which 6 animals
histological of 12 male function,
every
(range
fed with a standard
of cholesterol.
determined
rabbits
were
week
2,0-3,2;
rabbits
2 70 of cholesterol sacrificed
after
was
5,
of atheroma
comparable
in age,
was fed with the standard
Cholesterol other
diet for
examination rabbits,
from
and triglyceride
in both groups
(24).
weight,
diet levels
in
STRESS,LIPIDS,PLATELET
To obtain lipid
blood
samples
concentration,
(Statham
for measurements
as well
P 37 transducer),
anesthesia
(25 mg/kg
The catheters
0,5
were
solution
(20001. U. /ml).
avoided
by careful
premeasured -1,5
ml of blood
The rabbits
from
venous
catheter.
obtained
To quantify
platelet
in this
was
with the
and by discarding determination. by swimming
stressed
position
the orthostatic
blood
box,
(head
test,
obtained
pressure
which
up) for
or swimming were
20 min
by orthostasis.
into a tight fitting
measurements
the
from
and heart
blood the
rate were
various
was employed
under
1:lO)
under
dark
(20,21),
field
which
illumination.
illuminates
platelet
conditions,
the sample
rich
plasma
a novel
involves
a rotating
The dark field (50 ~1) of titrated
(obtained
by centrifugation
4 min).
The method
measuring
the platelet
by Schmid-Schonbein approximately specimen
and femoral
arteries
were
technique).
Specimen
judgement
of the whole
aorta)
Immediately
following
load that lead
to the rupture
diet,
is extensively
from
the rabbits
the aorta,
the myocardium
haemalaun
considered
under
taken
and from
and were
aggregation,
(20).
3 months
Histological
tosis.
were
into the vertical
aggregation
rheoscope
% Na-Citrate,
arteries
vena cava.
with heparin
stressed
squeezed
of arterial
method
condenser
After
and superior
mg/kg
catheter.
“rheoscope”
described
were
aggregation
cone -plate
at 500 g for
diet were
and after
Tracings
microphotometric
(3.8
chemical
animals
0,Ol
of the catheter
withdrawn
Before
via aortic
ml)
solution
the horizontal
for platelet
(0,l
for each
under
with a heparin-dextran
of heparin-dextran
these
inserted
of the blood
filling
the rabbits
15 min repeated. samples
Contamination
Otherwise
this purpose
was lifted
and filled
and
recording
with fentanyl
into the aorta
with high cholesterol
in 21’ C water. For
daily
aggregation
pressure
were
premeditation
volumetric
volume
blood
catheters
mg/kg)
flushed
of platelet
continous
chronic
Nembutal,
and dehydrobenzperidol
first
as for
483
CLLNPIXG
of abdominal
were
were
coronary, (stained
aorta
renal,
(after
macroscopic
taken
at the origin
representative
for
the formation
of excised
strips
carotid
by Sudan III and
always
the sacrifice,
sacrificed.
we determined of abdominal
of the renal of atheroma-
the maximum aorta.
After
484
STRESS,LIPIDS,PLATELET
correction
for the cross
computed.
In five
animals,
studied
by scanning
(25,26)
and Malissa
animals
were
and fixed
(27).
studied
stress
microscopy,
metal
of high cholesterol
was aorta
by Hess
electronmicrographs
of tension
and heavy
(in dynes/cm2)
as described
The scanning
state
Vo1.7,No.3
of the abdominal
surface
with a Cambridge
with carbon
period
the yield
the inner
electron
in its existing
and coated months
section,
CLUMPING
et al.
of five
SEM.
The aorta
using
6 % glutaraldehyd
(AU).
In two animals
was followed
was
was excised
by three
solution a three
months
of normal
diet.
RESULTS Rabbits
on high cholesterol
plasma
cholesterol
levels
increase
In the control
significantly
218) were
pressure There
was
rate
month.
cholesterol Atheroma
atheromatosis period
these
7 mg%,
levels
did not
during
of observation.
mean
at rest
was
arterial
after
224+
blood
the observation rabbits
arterial
mean
In
blood
15 beat/min.
pressure period
arterial
eight weeks
or
of three blood
period
of
I).
observed
and carotid were
diet,
rabbits
in mean
during
arteries.
observed.
of high cholesterol
aorta
and Royle
was not only present
femoral
11 mg% and 56:
as high as 2550 mg% (mean
by 19 mmHg
by King
were
I. Control
levels
rate
in the abdominal
suggested
Atheromatosis
time
(table
in table
in
period
in the hyperlipidemic
formation
atheromas
rabbits
significantly
diet
to a scheme
renal,
increase
in the control
rose
and heart
with time
month
In the control
9Ot 4mmHg,
59:
on normal
the three
increase
as depicted
were
cholesterol
observed.
However,
pressure
large
rabbits
was no significant
heart
rabbits
during
a steady
levels
and triglycerides
the hyperlipidemic 1’704:
showed
and triglycerid
of cholesterol
respectively.
diet
was qilantified
(13).
accordmg
In hyperlipidemic
the pathological
in the abdominal In the control
The atheromatosis diet as demonstrated
rabbits
examination. aorta,
rabbits
coronary, no signs
correlated in Figure
of
with the I. The
STRESS,LIPmS,PUTELET
485
CLUXPDJG
TABLlZ. I Effect
of cholesterol
vascular
yield
rich
diet on lipid
normal rabbits n= 12
hemodynamics
Imean art. pressure mmHg
briglycerides
mg%
mg%
59211
56+7
90+4
1
hyperlipidemic I rabbits
and
stress
1 Cholesterol i
I
level,
heart Irate1 min
ield
stress
107dyn/cm2
224+ I,15 -
64+10 I
’ 1704+218+ -
1300+361+
109+6+ -
+ p
