Arteriosclerosis in rabbit aorta induced by mechanical dilatation

Atherosclerosis Elsevier Publishing

Company,

ARTERIOSCLEROSIS

Amsterdam

IN

319

- Printed in The Netherlands

RABBIT

AORTA

INDUCED

BY

MECHANICAL

DILATATION BIOCHEMICAL

P. HELIN,

AND MORPHOLOGICAL

I. LORENZEN,

STUDIES

C. GARBARSCH

AND M. E. MATTHIESSEN

Connective Tissue Research Laboratories, Department of Dermatology, of Copenhagen; Gentofte Hospital, Medical Department C. Copenhagen; Histochemistry, Anatomy Department A, Uniuersity of Cofienhagen, (Revised,

Rigshospital, University Laboratory of Cyto- and Copenhagen (Denmark)

received September 22nd, 1970)

SUMMARY

The aortas ectomy

of male albino rabbits

catheter.

oped severe gross arteriosclerosis and exposure

to systemic

also identical

to those induced

intimal thickening

dilatation.

sulphates

and hydroxyproline glycosaminoglycans

2-week-old location

Finally

The microscopic

by catecholamines The

aortic

alterations

was increased.

The uptake

was also increased,

reflecting permability

in the dilated aortas. The biochemical of the vascular

and gross appearances

Key words:

hypoxia,

of hexosamine,

of the arteriosclerotic

and systemic

whereas

lesions induced chondroitin-4,6-

of [s?S]sulphate a stimulated

into the

synthesis

of

to 1251 labelled human

alterations

connective

were interpreted

tissue. The similarities lesions may indicate

tion of the aorta also plays a role in the development catecholamines

of the media were

and systemic

content

there was an increased

repair processes

arterial embol-

the animals devel-

of a type similar to that induced by catecholamines

hypoxia.

sulphated

serum albumin

dilatation,

was more severe and frequent in the arteriosclerotic

by the mechanical

these substances.

were dilated with a Fogarty

Two weeks after a single short-lasting

of arteriosclerosis

as

in the

that dilatainduced by

hypoxia.

Aorta - Aortic dilatation - Arteriosclerosis

- Chondroitin-4,6-sulphates

Collagen - Connective tissue - Dermatan sulphate - Glycosaminoglycans Heparan

su@hate

- Hyaluronic

acid - Hydroxyproline

--

- Mechanical

vascular injury - Repair processes - Wound healing

This work was supported by grants from the Danish State Research Foundation Heart Foundation. Atherosclerosis,

and the Danish

1971, 13: 319-331

320

P. HELIN,

I. LORENZEN,

C. GARBARSCH,

M. E. MATTHIESSEN

INTRODUCTION

A major

difficulty

morphological

alterations

arteriosclerosis

is, that

determined

in the estimation the time of existence

within reasonable

Under

physiological

strain by the arterial

the arterial

wall is subjected

in the blood pressure

seem to be of importance

increase in the mechanical studies suggest,

in animalsi,s.

be

factors

hypoxia4.

study involved

of aortic

Thus systemic

a biochemical

during the may be reIn previous

strain on the aortic

arteriosclerosis

hypoxia

analysis

of

these factors

of human arteriosclerosisiJ.

to the development

to systemic

to mechanical

Similarly

that an increase in the haemodynamic

blood pressure which dilates and elongates

The present

cannot

strain followed by a dilatation

that haemodynamic

of arteriosclerosis

in the pathogenesis

wall may be of importance in the arterial

usually

The increase

studies we have observed, of rabbits

of the alterations

blood pressure.

Experimental

and

limits.

sponsible for the development

exposure

of biochemical

tissue in human and experimental

conditions

systole causes a rhythmic the arteries.

and interpretation

in the vascular connective

following

causes an increase

the aorta. of the aortic glycosamino-

glycans and collagen as well as a study of the morphological

changes in arteriosclerosis

developed

dilatation

2 weeks after a single short-lasting

aorta in rabbits.

The mechanical

have features

in common

time of injury

was defined.

MATERIAL

diet*.

with an exaggerated

physiological

strain

included

The experiment

42 male albino

was carried

rabbits

out in October

of the aortas was performed

No. 12-OSO-5F. The diameter The insertion and probanidid catheter

to

and the precise

of the Danish

country

of age and weighing about 3 kg. The animals were fed a standard

dilatation

of the catheter anaesthesia.

was introduced

until the increased

was performed

into the artery

at the diaphragm

deflation

of the balloon was less than 1 sec. dilatation

of the aorta

femoral

sodium pentobarbital

artery was exposed.

was detected.

performed

was performed

The sham operation

in the dilated

* Karen M0lle rabbit pellets (“kanino”) vegetable fat, only traces of cholesterol. Atherosclerosis,

catheter

1971, 13: 319-331

The

to the arch of

The balloon was then

was removed and the artery ligated. The time from inflation

a sham operation.

as those

period. The

embolectomy

via an incision and advanced

the catheter

The

5

was inflated with 3 ml air and pulled rapidly distally

deflated,

underwent

arterial

under combined

The right superficial

resistance

during the shedding

with a Fogarty

strain, laboratory

of the inflated balloon was 11 mm and the length 18 mm.

aorta. The balloon of the catheter

ures

of the thoracic

on the aortic wall was presumed

AND METHODS

The study months

mechanical

strain inflicted

animals

containing

16%

in 20 rabbits included

exactly

while 22 controls the same proced-

with the only exception,

protein,

54%

to

carbohydrates

that the

and 3.6%

321

ARTERIOSCLEROSIS IN RABBIT AORTA INDUCED BY MECHANICALDILATATION

balloon of the catheter was not inflated. The animals were then divided into two groups: 11 dilated studies.

and

11 sham

intravenously

(carrier-free

100 ml solution

were used for biochemical

[a%]sulphate

and histochemical

had 1 mC of sodium

[asS]sulphate

diluted to a suitable

volume with a 10 mg/

9 dilated and 11 sham operated

animals were used for a perme-

study. On the 12th day these animals received an intravenous

ml 2%

human serum [IzsI]albumin

14th day all the animals pentobarbital.

arteriosclerosis

thoracic

a radioactivity

were killed by intravenous

of spontaneous

descending

carrying

The aortas were removed

Spontaneous frequency

injections

is rare in the descending

alterations

injection

is decreasing

of 300 mg sodium

thoracic

caudallys.

aorta from the first intercostal

arteries

aorta

Therefore

to the coeliac artery was

by planimetry

and a section,

between

caudal

aorta and used for microscopic

biochemical

was removed

analysis.

dry weight.

Samples

of the homogenate

of hexosamine

in water, lyophilized

were taken

of hydroxyproline

representing

the tissue was defatted

amount

of uranic

of the aortic

the amount of collagen

method

of BROWNIO following extraction

with acetone

acid in the glycosaminoglycans

of BOLLET et al.11. The method of the individual

The

for determination

by the method of PROCKOP AND UDENFRIEND~ as modified by JASSIN

AND ZIFFg. Thereafter

separation

[a%]sulphate

described

and a non-depolymerized

was determined

on testicular

after separation

fraction 12. The radioactivity

hyaluronidase-

into a depolymerized

was measured

as described

Beckman

[ 1s51]albumin

scintillation

and serum were measured

Histological

in a well-type

counter.

on the entire

scintillation

and

like in previous studiesla.

biosolve Beckman@

liquid

total

by the methods

MAHIN AND LOFBERG14 after addition of 20 y. BBS-3 LS-250

The

by the orcinol

by THUNELL~~ was used for isolation

glycosaminoglycans,

radioactivity

and ether.

was determined

of the glycosaminoglycans

digested sodium salts of the glycosaminoglycans

respectively,

and dried to

as the difference between wet and

by the method of ELSON AND MORGAN~as modified by BOAST.

On similar samples the content was determined

aorta

studies.

and only the intima plus the media were used for

The tissue was homogenized

weight. The water content was determined

content

the cranial two thirds and the

studies

The adventitia constant

thoracic

and the only the

2 mm in width, was cut from the borderline one third of the descending

of 0.4

of about 20 PC. On the

and cut longitudinally.

used in this study. The inner surface area was estimated

Biochemical

injected

of sodium sulphate).

The remaining ability

operated

On the 12th day these rabbits

The

dry tissues

by

and using a

radioactivities

in

and on serum samples,

counter.

studies

The specimens

for microscopic

examination

were fixed in 0.5 y. cetylpyridinium

chloride in neutral buffered 4 o/oformalin. The following methods of staining were used: (1) haematoxylin--eosin; elastic

tissue;

(2) van Gieson staining

(4) silver staining

for argyrophilic

for collagen;

(3) orcein

fibres according Atherosclerosis,

staining

for

to Bielschowsky1971, 13: 319-331

322

P. HELIN, I. LORENZEK, C. GARBARSCH, M. E. MATTHIESSEN

TABLE

1

Body weights

Ilv~j weights

(kg)

changesa ( %)

aortas (mg)

aortas ( % of dry weight)

Innev surface areas qfthe thwack aortas (Cm=)

2.99&0.14b 3.05*0.13 x,s.e

5.58i2.99 4.36&2.11 N.S.

67.24 i 6.85 42.68h2.49 < 0.01

269.42*9.25 240.17&6.12 < 0.02

7.51 kO.42 5.84*0.23 < 0.01

initial

Dilated (11)~ Control (11) P valuesd

m’ater contents

ofthe thwack

ofthe thoracic

__~ a b c * e

Changes in body weights from start to end of experiment. Mean & standard deviation of mean. Number of observations. Students’ t test. N.S.: not statistically significant.

Maresch as modified by LILLIE~~; aminoglycansi6; distinguish

with testicular the calcium Sections

(5) 0.1 o/0toluidine

blue in 30 o/oethanol for glycos-

(6) 0.1 y. toluidine blue in McIlvaine

between

guish between

Per cent of initial weight.

sulphated

and non-sulphated

chondroitin-4,6-sulphates hyaluronidase red (Nuclear

decalcinated

(Fluka)

buffers (pH 2.2, 3.0 and 5.0) to

glycosaminoglycansi7.

and dermatan-heparan was performed

fast red) method

To distin-

sulphates,

digestion

in some of the specimens;

of McCeeeRusselrs

for calcium

(7)

salts.

at pH 2.2 were used as controls.

RESULTS

During same extent

the study the experimental (Table

and control

animals

1). The dry weight and the water content

were higher in the dilated animals, of these animals were enlarged.

gained weight to the of the thoracic

and the inner surface areas of the thoracic

aorta aortas

All the dilated aortas had changes visible to the un-

armed eye. Two different types of lesions were seen. All the aortas in the dilated group

Figs. l-4. Thoracic aorta of rabbits control rabbit (Fig. 4). Fig. 1. Arteriosclerotic Atherosclerosis,

2 weeks after mechanical

plaques neighbouring

1971, 13: 319-331

the intercostal

dilatation

arteries,

(Figs.

l-3)

and of a

ARTERIOSCLEROSIS

Fig. 2. Bean-shaped

IN RABBIT AORTA INDUCED

BY MECHANICAL

DILATATION

323

lesions.

Fig. 3. Aneurysms.

Fig. 4. Normal

aorta.

showed oval plaques measuring about 3 mm x 4 mm and surrounding the intercosta1 arteries (Fig. 1). The plaques which were white with slightly elevated edges, were now and then also seen in other areas of the thoracic aorta. The other less frequent type of lesion was bean-shaped bulges of the aortic wall (Fig. 2). These lesions measured about 5 mm x 15 mm and were usually located in the distal part of the thoracic aorta. In some aortas the gross alterations had the character of thin-walled aneurysms (Fig. 3). All specimens removed from the distal aortas for microscopic examination had gross alterations. Microscopic changes in these sections occurred in the intima and the media. From Table 2 it appears that there was no difference in the frequency of the intimal and the medial changes. Isolated intimal and medial alterations occurred only in the specimens from 2 animals. Atherosclerosis,

1971, 13: 319-331

P. HELIN,

324

Fig. 5. Intimal thickening blue at pH 5. x 160.

TABLE

C. GARBARSCH,

in rabbit aorta 2 weeks after mechanical

M. E. MATTHIESSEN

dilabtation. Staining: tcAuidine

2

MICROSCOPIC AFTER

I. LORENZEN,

ALTERATIONS

MECHANICAL

Experimental group Control group

Experimental group Control group

Experimental group Control group

IN

THE

DILATATION

LOWER

AORTA

OF

MALE

ALBINO

RABBITS

2 WEEKS

changes

Intimal thickening

Medial changes

Advent&al

10/11a o/11

IO/11 3/11

o/11 o/11

Intimal thickening only

Medial changes only

Simultaneous intimal and medial changes

l/11& o/11

l/11 3/11

9/11 o/11

Medial changes

Medial changes with calcijication

Medial changes without calc$ication

Metachromatic “lakes” only

10/11a

7/11

3/11

2/11

3/11

o/11

3/11

3/11

& Number of animals out of total number. Atherosclerosis,

THORACIC

OF AORTA

1971, 13: 319-331

ARTERIOSCLEROSIS

IN RABBIT AORTA INDUCED

In most specimens

the endothelium

thelial layer could not be identified.

BY MECHANICAL

was present,

DILATATION

but in some sections

A subendothelial

thickening

325 the endo-

was a typical

finding

(Fig. 5). The appearance varied from cushion-shaped elevations in some areas to almost normal intima in others. The thickening contained stratified smooth muscle cells arranged

concentrically

around

the aortic

lumen.

However,

smooth

muscle

cells in the basal intima were often longitudinally oriented. In some specimens cells were found with their long axis radially to the aortic lumen. The amorphous ground substance

showed a metachromasia

at lower pH levels. The metachromasia

which was distinct disappeared

at high pH levels and fainter

almost entirely

following digestion

with testicular hyaluronidase. Collagen and delicate elastic fibres were also present in minor amounts. The changes in the media consisted of necrotic foci with and without calcification and metachromatic “lakes” with declining frequency in the order mentioned (Table 2). The necrotic foci appeared as areas of cells, without nuclei and without cytoplasmic basophilia (Fig. 6). The elastic membranes were fragmented and/or straightened. The calcified foci were oblong in transverse sections and the elastic lamina luminal and basal to the foci were straightened, whereas they often exhibited a wavy pattern at the ends of the foci. Surrounding the foci was amorphous intercellular

substance

showing

distinct

metachromasia

what fainter metachromasia at low pH (Fig. 7). It testicular hyaluronidase. Collagen fibres were seen chromatic intercellular substance. Some perifocal observed in the same areas as the increase in collagen

at high pH levels

and

a some-

disappeared after digestion with at the same places as the metaaccumulation of cells might be and metachromatic intercellular

Fig. 6. Medial necrosis in rabbit aorta 2 weeks after mechanical blue at pH 5. x 160.

dilatation.

Atherosclerosis,

Staining:

toluidine

1971, 13: 319-331

326

P.

HELIN,

I. LORENZEN,

C. GARBARSCH,

Fig. 7. Rabbit aorta 2 weeks after mechanical dilatation. The p&focal Note the stretched and wavy elastic membranes. Staining: toluidine

substance.

Usually

the intimal

might be observed Three

TABLE

in the control

“lakes”

Biochemical containing

in the adventitia

substances

part of the

number

of cells

between

group exhibited

mild alterations

in the form of

the elastic membranes.

in the dilated group (Table 3), reflecting

of hexosamine-

an increase

of glyco-

3

THORACIC

Group

Dilated (1 l)b Control (11) P values a b c d

at the peripherial

analysis revealed an increase in the aortic content

THE CONCENTRATION AND IN

was located

were rare, but an increased

outside the medial foci.

animals

metachromatic

metachromasia is intensive. blue at pH 5. x 160.

and the medial changes occurred in the same sections

(Table 2). As a rule the intimal thickening medial foci. Changes

M. E. MATTHIESSEN

AORTA

OF

TOTAL

MALE

AMOUNT

RABBITS

2

OF WEEKS

He.%kXZW&i?Ze

AFTER

HYDROXYPROLINE

MECHANICAL

DILATATION

Hydroxyproline

dried tissue (/&%5

total content I/49

dried tissue (MmgJ

total content (I@)

6.45hO.27” 6.27+0.21 N.S.C

425.62*41.02 264.72+ 13.38 < 0.01

21.3Oh1.04 22.68* 1.02 N.S.

1396.59~130.15 967.95* 72.45 < 0.02

Mean + standard deviation of mean. Number of animals. N.S.: not statistically significant. Determined on isolated glycosaminoglycans.

Atherosclerosis,

HEXOSAMINE,

1971, 13: 319-331

AND OF

URONIC AORTA

Hexosamine to orcinol ratiod

0.99&0.03 1.07&0.04

N.S.

ACID

4

AND

AMOUNT

IN THE THORACIC

OF MALE

RABBITS

7.29 4.62 11.27 2.34

73.31 * 31.81 & 103.51 f 13.89 *

P v&Lea N.S.c N.S. N.S. N.S.

1.28 & 0.16 0.56 f 0.05 1.51 & 0.11 0.21 * 0.03

1.14 * O.lOb 0.47 4 0.06

1.56 & 0.08 0.21 * 0.03

dilated

Total amount (pug)

AORTA

control (11)

pg hexosamine/mg dried defatted tissue

OF GLYCOSAMINOGLYCANS

dilated (I 1)

Concentration,

TOTAL

a Students’ t test. b Mean f standard deviation of mean c N.S.: not statistically significant.

Hyaluronic acid Heparan sulphate Chondroitin-4,6sulphate Dermatan sulphate -

Groq5

OF AORTA

THE CONCENTRATION

TABLE

N.S. N.S. < 0.02 N.S.

63.74 & 5.62 9.20 * 1.34

MECHANICAL

54.63 f 7.08 24.12 & 2.44

AFTER

P value

WEEKS

control

2 DILATATION

328

P. HELIN, I. LORENZEN, C. GARBARSCH, M. E. MATTHIESSEN

TABLE

5

UPTAKEOF OF

AORTA

[%jSULPHATE OF

MALE

IN

Dilated (11)~ Control (11) P values

THE

2

RABBITS

ISOLATED

WEEKS

SULPHATED

AFTER

GLYCOSAMINOGLYCANS

MECHANICAL

DILATATION

AND

OF

Chondroitin-4,6sulphatea

Heparan sulphate plus dermatax sulphatea

17074.8& 1184.5b 6228.0* 375.7 < 0.001

4914.4*407.0 2161.1*153.9 < 0.001

[lz51jALBUMIN

AORTA

71.42*4.37 49.3163.24 < 0.001

a Counts/min per 10 mg dry defatted tissue. b Mean 5 standard deviation of mean. c Number of animals. * [125I]albumin activity in aorta (counts/100 xc/l0 mg of dried tissue) as per cent of the serum activity (counts/100 sec/lO pl serum). Nine dilated rabbits and 11 controls.

proteins

and

sulphates

(Table

increase,

but

sulphate

into all the fractions

aortas

the changes

was increased

aortic

glycosaminoglycans

content

of chondroitin-4,6seemed

The uptake

glycosaminoglycans

of controls.

also to of [35S]-

of the dilated

The increase

as well as the pool of heparan

sulphate

involved

the

plus dermatan

(Table 5).

of hydroxyproline

(Table 3). The concentrations hydroxyproline

to that

content

significant.

of the sulphated

as compared

to the same extent

The total

was increased

total other

were not statistically

chondroitin-4,6-sulphates sulphate

The 4). The

glycosaminoglycans.

was increased

was also increased

of hexosamine,

did not change.

Finally,

the individual

the radioactivity

in the dilated

group

glycosaminoglycans

and

of [125I]albumin

in aorta

in the dilated aortas (Table 5). This is true when the radioactivity

related to the dry weights of the aortas

was

(listed in Table 5) as well as to the surface

areas (not listed). DISCUSSION

The arteriosclerotic to a mechanical

damage

diffusion secondary

lesions in the present experiment of the aortic

to the compression

bly of little importance,

and stretching

since the dilatation

hand, it cannot be excluded, injury,

wall. Anoxia

connective

following

mechanical

injury

vascular

connective

collagen

fibres.

lesion induced using

development induced

The similarity

between

in the abdominal

a balloon-dilatation

Atherosclerosis,

by the balloon

without

1971, 13: 319-331

mechanical

tissue, per se may interfere

of the lesions. Two factors

tissue, in particular

On the other

the primary

oxygen diffusion in the aortic wall. This may lead to a secondary tance to the further

due to impaired

of the aortic wall are presuma-

was of very short duration.

that the alterations

e.g. oedema of the vascular

are probably primarily due

and hypoxia

catheter:

hypoxia

with the of impor-

may be involved in the

(a) An overstretching

of the

the smooth muscle cells, the elastic and the the present

aorta of rabbits traction

lesion and the arteriosclerotic

by B~UMGARTNER

may support

AND sTUDERlg

this interpretation.

(b) The

329

ARTERIOSCLEROSIS IN RABBIT AORTA INDUCED BY MECHANICAL DILATATION

intimal

layer may be damaged

endothelial

cells. This

changes in the present study ficial scratching

are similar

and exposure

may

induced

arteries

were common

These similarities dilatation,

suggest,

exposure

of the gross alterations conditioned column.

induced

by

of the distal

starts

around

implicates

thoracic

Our previous

studies

suggest,

on the connective mechanical

opment

of experimental hypoxia

explain

more, the microscopic aortic arteriosclerosis

arteriosclerosis

catecholaminessIJ2.

extent

alterations

injury

a removal

following

in the balloon

mechanical

hypoxia

in all pro-

dilatation,

exposure

to

mechanical

injury

of

of the injury varies. Further-

and by intravenous

the intimal

experiment,

thickening

which possibly

injections

of

were not as

implicates

that the same type of glycosaminoglycans The predominating Some dermatan

since a faint metachromasia

hyaluronidase

for 3 h. Finally,

higher pH levels suggest the presence of hyaluronic Biochemical

Therefore,

to some

cells.

tests suggest,

also be present,

tion with testicular

aortic

plays a role in the devel-

by others following

however,

glycans seem to be chondroitin-4,6-sulphates. however,

induced

to the effect of noradrenaline

as in the present study. This may be explained by a more

part in the medial and intimal alterations. may,

of the

of the media are similar to those described by us in

by systemic

of endothelial

The histochemical

arelativelygreater

in the intima and the media observed in the present

In these studies,

and as constant

arteries. The

of catecholamines.

to those observed

induced

to the

properties

the predominance

of the noradrenaline

secondary

aortaIs~s0. This is true even if the type and the duration

severe intimal

aorta

that also the atheromatosis

as well as local tissue hypoxia

alterations

are similar

The

arteries is

aorta in the present experiment.

on the pathogenesis

and injections

The microscopic

pronounced

of the

the orifices of the intercostal

that tissue hypoxia

dilatation

factor is

of injury.

the intercostal

e.g. the binding

This may

induced

of catechol-

The obvious

tissue cells of aorta is a factor of importance.

bability

experiment

in common.

in the balloon experiment

aorta.

lesions in this part of the thoracic

arteriosclerosis23

arteriosclerosis

and injection

to the areas neighbouring factors

of experimental

during all three types

parts of the aortic wall. It is noteworthy,

tapering of the aorta caudally

systemic

hypoxia

mechanisms

anatomical

of the gross lesions

It may also be due to differences in the physico-chemical

by hyperlipaemia

dilatation

super-

of catecholamines

the location

that experimental

of the aorta, which is pronounced

of the various

on the

the intimal

as “bean-shaped

injections

to the three types

to systemic

amines may have some pathogenetic

probably

lesions described

by intravenous

hypoxia sI,ss. Furthermore,

to systemic

arteriosclerosis.

vertebral

between

by BJ~RKERUD~O following

of the arteriosclerotic

by mechanical

location

the similarity

and those described

to those

close to the intercostal

the dilatation

explain

of the intima.

The gross appearance bulges”

by the pressure and the friction of the balloon

hypothesis

studies of the vascular connective

sulphated

takes

glycosamino-

and/or heparan sulphate was observed after diges-

the decrease in metachromasia

at

acid. tissue changes following mechan-

ical injury of the arterial wall are very sparse. VON BERLEPSCH AND STUDER~~ dilated Atherosclerosis,

1971, 13: 319-331

P. HELIN, I. LORENZEN, C. GARBARSCH, M. E. MATTHIESSEN

330 the abdominal

aorta of rabbits

1.2 kg/cmz. They observed

for 12 min with a balloon catheter

an increase in the concentration

only a few days. The concentration

of the galactosaminoglycans

ated pool of chondroitin-4-sulphate, increased

to a maximum

next 6 months. aminoglycans tation

injury.

increased.

In our study of the thoracic revealed, that dermatan By contrast,

the total

aorta,

and dermatan

and decreased

between

the fractionation

of the galactos-

amount

of chondroitin-4,6-sulphates

the concentration

and the total

of the aortic wall, among these calcium

content

lations in relation to focal lesions suggests,

that the increase

to the vascular

determined

sulphate

of particular

as chondroitin-4,6-sulphates reflects

a stimulated

synthesis

The lack of changes in hyaluronic the observation granulation

increased

uptake

of all 3 sulphated

wound healing.

The sulphated

in the aortic

of collagen

arteriosclerosis. non-specific

content

The observation of repair.

accords with studies on

increase in hyalurincrease

at a

acid25326. There-

tissue. A pronounced

dependence

of

upon the age of the vascular lesions has earlier arteriosclerosi?.

of hydroxyproline

has not been reported

processes

[%]sulphate

experimental

glycosaminoglycans

by one of us in catecholamine-induced

The increase

the possi-

in the present study may reflect 2-week-

old processes of repair of the vascular connective the changes in the glycosaminoglycans

of

glycosaminoglycans”‘.

for a longer period than hyaluronic

fore, the changes in the glycosaminoglycans

been demonstrated

of

acid 2 weeks after the dilatation

tissue suggest, that there is an early and short-lasting

onic acid during

amount

in the dilated aortas was

of VON BERLEPSCH AND STUDER 24. Similarly,

slower rate and remain elevated

amount

in the total

(Table 3) excludes

high hybridity

13. The

The histo-

with accumu-

injury. The lack of changes in the

to orcinol ratio of the glycosaminoglycans

bility that dermatan probably

is related

increase in other

salts and collagen.

of the glycosaminoglycans

chondroitin-4,6-sulphates

The

of chondroitin-4,6-

chemical evidence of an uneven distribution

hexosamine

in aorta

of these components.

sulphates is explained by a dilution effect caused by the simultaneous components

sulphate)

slowly during the

sulphate did not change 2 weeks after the dila-

No changes were observed in the concentrations

discrepancy

acid lasting

(i.e. the non-fraction-

chondroitin-6-sulphate

2 weeks after the dilatation

using a pressure of

of hyaluronic

previously

accords with the interpretation Further

studies

reflecting

an increased

in this type of experimental

are, however,

of the alterations necessary

as

to support

our theories. In contrast activity

to our findings in the hypoxia

of human

experiment.

serum [125I]albumin

The increased

human serum albumin.

radioactivity

Whether

removal of some of the endothelial vascular

connective

Atherosclerosis,

1971,

study, we observed an increased radio-

in the arteriosclerotic may reflect

of the present permeability

this is due to a direct damage of endothelial cells or is part of the regenerative

tissue remains to be settled.

13: 319-331

aortas

an increased

to

cells, a

processes of the

ARTERIOSCLEROSIS

IN RABBIT AORTA INDUCED

BY MECHANICAL

DILATATION

331

REFERENCES 1 TEXON, M., The role of vascular dynamics in the development of atherosclerosis. In: M. SANDLER

AND G. BOURNE (Eds.), Atherosclerosis and Its Origin, Academic Press, New York and London, 1963, p. 165. 2 PALMA, E. C., Hemodynamic arteriosclerosis, J. Cardiovasc. Sung., 1967, 8: 198. 3 GLAGOV. S., Hemodvnamic factors in localization of atherosclerosis, Acta Cardiol.. 1965, Suppl. XI: 311. 4 HELIN, P. AND I. LORENZEN, Arteriosclerosis in rabbit aorta induced by systemic hypoxia, Angiology, 1969, 20: 1. 5 GARRARSCH, C., M. E. MATTHIESSEN, P. HELIN AND I. LORENZEN, Spontaneous aortic arteriosclerosis in rabbits of the Danish country strain, Atherosclerosis. 1970, 12: 291. 6 ELSON, L. A. AND W. T. J. MORGAN, A calorimetric method for the determination of glucosamine and chondrosamine, Biochem. J., 1933, 27: 1824. 7 BOAS, N. F., Method for determination of hexosamines in tissues, J. Biol. Chem., 1953, 204: 553. 8 PROCKOP, D. J. AND S. UDENFRIEND, A specific method for the analysis of hydroxyprodne in tissue and urine, Analst. Biochem., 1960, 1: 228. 9 JASSIN, H. E. AND M. ZIFF. Relationship between soluble collagen and urinary hydroxyproline in lathyritic rat, Proc. Sot. Exptl. BioZ. Med., 1962, 110: 837. 10 BROWN, A. H. Determination of pentose in the presence of large quantities of glucose, Arch. Biochem., 1946, 11: 269. 11 BOLLET, A. J.. D. V. ANDERSON AND W. F. SIMPSOP~,The measurement of tissue acid mucopolysaccharides, J. CZin. Iwest.. 1958, 37: 858. 12 THUNELL, S., Procedures for microscale investigation of vessel wall glycosaminoglycans, Acta Univ. Luuzd., 1967, Sectio II, No. 9. 13 HELIN, G., P. HELIN AND I. LORENZEN, The aortic glycosaminoglycans in arteriosclerosis induced by systemic hypoxia, Atheroscleroszs, 1970, 12: 235. 14 MAHIN, D. T. AND R. T. LOFBERG, A simplified method of sample preparation for determination of tritium, carbon-14 or sulfur-35 in blood or tissues by liquid scintillation counting, Analyst. Bzochem., 1966, 16: 500. 15 LILLIE. R. D.. Histobatholopic Technic and Practical Histochemislrv. McGraw-Hill, New York, 1965, pp. 539;553, 5j5. 16 KRAMER, H. AND G. M. WINDRUM. The metachromatic staining reaction. ”I. Histochem. Cytochek., 1955, 3: 227. 17 KRYGIER, A. AND K. KASPRZYK, The influence of hydrogenion concentrations and some other ions on metachromasia in staining mucopolysaccharides with toluidine blue, Acta Med. Pal., 1961, 2: 123. 18 PEARSE, A. G. E., Histochemistry, Theoretical and Apfilied, Churchill, London, 1961, p. 933. 19 BAUMGARTNER, H. R. AND R. STUDER, Gezielte tiberdehnung der Aorta abdominalis am normound hypercholesterinaemischen Kaninchen, Pathol. Microbial., 1963, 26: 129. 20 BJGRKERUD, S., Reaction of the aortic wall of the rabbit after superficial, longitudinal, mechanical trauma, Virchows Arch., Abt. A. Pathol. Anat., 1969, 347: 197. 21 GARBARSCH,C., M. E. MATTHIESSEN, P. HELIN AND I. LORENZEN, Arteriosclerosis and hypoxia, Part 1 (Gross and microscopic changes in rabbit aorta induced by systemic hypoxia. Histochemical studies), J. Atheroscler. Res., 1969, 9: 283. 22 LORENZEN, I., Experimental Arteriosclerosis, Munksgaard, Copenhagen, 1963, p, 20. 23 HELIN, P., I. LORENZEN, C. GARBARSCH AND M. E. MATTHIESSEN, Arteriosclerosis induced by noradrenaline, Atherosclerosis, 1970, 12: 125. 24 VON BERLEPSCH, K. AND A. STUDER, Acid mucopolysaccharides after overdilatation of the aortic wall of the rabbit, Angiologica, 1969, 6: 105. 25 ANTONOWICZ, I. AND E. KODICEK, The effect of scurvy on glycosaminoglycans of granulation tissue and costal cartilage, Biochem. J., 1968, 110: 609. 26 CORNER, R. W., Changes in glycosaminoglycan composition associated with maturation of regenerating rabbit tendon, Arch. Biochem. Biophys., 1968, 128: 34. *7 LORENZEN, I., Alterations in acid mucopolysaccharide and collagen of rabbit aorta related to age of epinephrine-thyroxine induced arteriosclerotic lesions, Acta Endocrinol., 1962, 39: 615.

Atherosclerosis,

1971, 13: 319-331