colágeno e envelhecimento

8/10/2019 colgeno e envelhecimento

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Recebido em 27.08.2002. / Received in August, 27th of 2002.Aprovado pelo Conselho Consultivo e aceito para publicao em 01.04.2003. / Approved by the Consul tive Counci l and accepted fo r publicat ion in April, 01st of 2003.* Trabalho realizado no Departamento de Morfologia da Faculdade de Medicina da Universidade Federal do Cear. / Work done at Mophology Department of "Faculdade de Medicina da

Universidade Federal do Cear"

1 Departmento de Morfologia, Universidade Federal do Cear, Fortaleza, CE, Brasil. /Dept. of Morphology, Federal University of Cear, Fortaleza, CE, Brazil2 Departmento de Patologia e Medicina Legal, Universidade Federal do Cear, Fortaleza, CE, Brasil. /Dept. of Pathology and Legal Medicine, Federal Universityof Cear, Fortaleza, CE, Brazil.

3 Estudantes de Medicina da Universidade Federal do Cear, Fortaleza, CE, Brasil. /Medical Students, Federal University of Cear, Fortaleza, CE, Brazil.

2003 by Anais Brasileiros de Dermatologia

Estudo das alteraes relacionadas com a idade na pelehumana, utilizando mtodos de histo-morfometria e

autofluorescncia*

Study of age-related changes in human skin usinghistomorphometric and autofluorescence approaches*

Reinaldo B. Ori1 Francisco Valdeci A. Ferreira2 rika N. Santana3Mariana R. Fernandes3 Gerly A. C. Brito1

Resumo: FUNDAMENTOS - O processo de envelhecimento tecidual evidente nas modificaes visveis na pele, resultando em impor-tantes implicaes psicolgicas para o indivduo e crescente interesse cientfico.OBJETIVOS - O presente trabalho objetivou analisar as alteraes da pele normal com o envelhecimento mediante estratgias de his-tomorfometria e autofluorescncia.MTODOS - Foram coletadas amostras de pele do abdmen de 18 cadveres, incluindo cinco indivduos jovens (menos de 20 anos), seteindivduos com idade intermediria (20-60 anos) e seis indivduos idosos (mais de 60 anos). Foram feitos cortes histolgicos em parafi-na seguidos de colorao pela Hematoxilina-Eosina (H&E) e pelo tricrmio de Van Gieson-elastina. Avaliaram-se a espessura da epidermee derme, e a superfcie de contato epidermo-drmica. Investigaram-se ainda as modificaes qualitativas do aparelho colgeno-elstico,considerando sua disposio espacial na derme. Espcimes corados emH&E tambm foram utilizados para autofluorescncia.RESULTADOS - A espessura da epiderme e derme do grupo idoso foi significativamente diminuda (p


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426 Ori, Santana, Fernandes, Ferreira & Brito

An bras Dermatol, Rio de Janeiro, 78(4):425-434, jul./ago. 2003.

INTRODUOOs tecidos gradualmente passam por mudanas de

acordo com a idade, sendo que, na pele, essas alteraes somais facilmente reconhecidas.1,2 Atrofia, enrugamento,

ptose e lassido representam os sinais mais aparentes deuma pele senil.3-5

Mudanas nas caractersticas da pele humanadurante o envelhecimento so freqentemente determinadas

por foras ambientais ou extrnsecas, tais como radiaoultravioleta,6,7 assim como por fatores intrnsecos,8-10 algunsdeles relacionados com alteraes no tecido conjuntivo daderme.11-13 Alteraes no tecido conjuntivo, que atua comoalicerce estrutural para epiderme, delineiam essas mudan-as na aparncia externa, que so refletidas no estrato cr-neo.14,15 As modificaes do aparelho colgeno-elstico aolongo da vida estabelecem uma base morfolgica substan-cial para compreender as adaptaes bioqumicas e bio-mecnicas da pele com a idade.16-19 A espessura da pele e

suas propriedades viscoelsticas no dependem apenas daquantidade de material presente na derme, mas tambm desua organizao estrutural.20,21

Para estudar os mecanismos envolvidos no envelhe-cimento, portanto, necessrio compreender melhor asmudanas estruturais e funcionais que ocorrem com oavanar da idade, distinguindo as alteraes que possamrepresentar um processo intrnseco daquelas que refletemefeitos patolgicos cumulativos ou agresses ambientaisexternas.22,23 Convm ainda considerar que, independente daidade do indivduo, a espessura total da pele, espessura rela-tiva da epiderme e derme, distribuio e fentipo da popu-

lao celular na derme, presena de anexos cutneos e den-sidade da microvasculatura e de nervos variam conforme aregio do corpo.24-26

Exames histolgicos e ultra-estruturais da pele, apar tir de espcimes obt idos por autpsia, documentamimportantes alteraes estruturais na epiderme, junoepidermo-drmica, derme e anexos epidrmicos. Comintuito de investigar as mudanas cronolgicas da pelehumana, foram utilizados mtodos de microscopia defluorescncia, a partir de colorao por H&E e histomor-fometria, possibilitando, dessa forma, retratar as modifi-caes teciduais ao longo da vida, no que diz respeito asua textura e conformao, relacionando com sua mode-

lao biomecnica no espao.

MATERIAIS E MTODOSAmostras de pele foram coletadas de 18 cadveres,

incluindo cinco indivduos jovens (abaixo dos 20 anos),sete indivduos com idade intermediria (20-60 anos) e seisindivduos idosos (com mais de 60 anos). Usaram-se comocritrios de incluso pacientes de ambos os sexos, sem dis-criminao de raa, cuja causa da morte no inclussemdoenas que afetam diretamente a pele. Foram excludos dotrabalho os indivduos com doena dermatolgica ousistmicas ligadas diretamente a alteraes cutneas

INTRODUCTION

Tissues gradually go through changes in accordance

with age, and, in the skin, those alterations are more easily

recognized. 1,2Atrophy, wrinkles, ptosis and looseness repre-

sent the most apparent signs of a senile skin. 3-5

Changes in the characteristics of human skin during

aging are frequently determined by environmental or

extrinsic forces, such as ultraviolet radiation, 6,7 as well as

by intrinsic factors,8-10some of them related with alterations

in the conjunctive tissue of the dermis.11-13Alterations in the

conjunctive tissue which acts as a structural foundation for

the epidermis, delineate these changes in the external

appearance that are reflected in the corneum stratum. 14,15

The modifications of the collagen-elastic apparatus

throughout a lifetime establish a substantial morphological

basis from which to understand the biochemical and bio-

mechanical adaptations of the skin with age. 16-19 The thick-

ness of the skin and its viscoelastic properties do not depend

only on the amount of material present in the dermis, butalso on its structural organization.20,21

To study the mechanisms involved in aging, there-

fore, it is necessary to understand the structural and func-

tional changes that occur with the advancement of age,

distinguishing between the alterations that can represent an

intrinsic process, and those that reflect cumulative patho-

logical effects or external environmental aggressions.22,23It

is well to consider that, independent of the individual's age,

the total thickness of the skin, relative thickness of the epi-

dermis compared with the dermis, distribution and pheno-

type of the cellular population in the dermis, presence of

cutaneous enclosures and density of the microvasculatureand of nerves, can all vary according to which area of the

body is being examined.24-26

Histological and ultra-structural exams of the skin,

based on specimens obtained by autopsy, document impor-

tant structural alterations in the epidermis, dermoepider-

mal interface, dermis and epidermal annexes. With the

intention of investigating the chronological changes in

human skin, microscopic fluorescence techniques were

used, starting from coloration by H&Eand histomorphome-

try, making possible, in this way, to portray the tissue modi-

fications along the course of a lifetime together with their

implications regarding the changing textures and confor-

mations, related to its spatial biomechanical modeling.

MATERIAL AND METHODS

Skin samples were collected from 18 cadavers,

including five young individuals (below 20 years of age),

seven individuals of middle-age (20-60 years) and six

elderly individuals (more than 60 years of age). The inclu-

sion criteria were patients of both sexes, without discrimi-

nation of race, whose cause of the death did not include

diseases that affect the skin directly. Excluded from this

work were individuals with dermatological disease or with

case histories reporting systemic pathologies linked direct-


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Ori, Santana, Fernandes, Ferreira & Brito 427


ly to cutaneous alterations. Skin samples measuring 1cm2

were collected from the abdominal areas, 2 cm above the

umbilicus. As was indicated by Faria et al .27 andGonalves1, the skin of the abdomen is best adapted for the

study of alterations caused by the aging process. The speci-

mens were obtained during the autopsy procedure done in

the Department of Pathology and Legal Medicine of the

Federal University of Cear (UFC). The protocol of the

experiment was previously approved by the Committee of

Ethics and Research of the Walter Cantdio/UFCTeaching

Hospital. The skin samples were immediately placed in a

10% formalin buffer solution for 24 hours after which they

were embedded in paraffin and six micrometers sections

were made. The paraffin was then removed and the sam-

ples were moisturized, dyed and mounted on histological

slides. All specimens were dyed with H&Efor later analy-

sis by the autofluorescence method. The Hematoxylin and

Eosin and Van Gieson-elast in trichrome methods, as

described by Kiernan, 28 were chosen for the study of theskin morphology.

The histological sections of skin were analyzed

using a binocular optical microscope fitted with a mil-

limeter scale (Leitz Wetzlar Germany Periplan, GF x10).

The thicknesses of both the epidermis and dermis were

measured, as well as the contact surface between them.

The epidermis and the dermis were measured at 10 dif-

ferent sites in each sample: five measurements in the

papillary layer and five in the layer of epidermic ridges

(Graph 1). Following this, for each section a mean value

relatadas no pronturio. Amostras de pele medindo 1cm 2

foram colhidas da regio abdominal, 2cm acima da cicatrizumbilical. Como indicado por Faria et al.27 e Gonalves,1 a

pele do abdmen apropriada para o estudo das alteraescausadas pelo processo de envelhecimento. Os espcimesforam obtidos durante o procedimento de autpsia realiza-do no Departamento de Patologia e Medicina Legal daUniversidade Federal do Cear (UFC). O protocolo experi-mental foi previamente aprovado pelo Comit de tica ePesquisa do Hospital Universitrio Walter Cantdio/UFC.As amostras de pele foram imediatamente fixadas emsoluo de formalina tamponada a 10% por 24h e embe-

bidas em paraf ina. Foram realizadas seces de seismicrmetros de espessura dos blocos de parafina; em segui-da, as peas foram hidratadas aps a remoo da parafina,coradas e montadas em meio de Entelan nas lminas his -tolgicas. Todos os espcimes foram corados em H&Epara

posteriormente serem analisados pelo mtodo de autofluo-

rescncia. O mtodo de Hematoxilina-Eosina e o tricrmiode Van Gieson-elastina, como descritos por Kiernan,28 fo-ram escolhidos para estudar a morfologia da pele.

Os cortes histolgicos de pele foram analisadosutilizando um microscpio ptico binocular provido deocular milimetrada (Leitz Wetzlar Germany Periplan, GFx10). Foram avaliadas a espessura da epiderme e derme,e a superfcie de contato entre elas. A epiderme e aderme foram medidas em 10 diferentes locais em cadaamostra: cinco medidas na papila e cinco nas cristasepidrmicas (Grfico 1). A seguir, para cada corte foi

Grfico 1: Diagrama ilustrando omtodo para anlise morfomtricada epiderme, derme e superfciede contato epidermo-drmica. Emcada amostra de pele, foram feitas10 medidas da superfcie da epi-derme at a juno epiderme-derme, sendo cinco medidas nacrista epidrmica (posicionando aocular milimetrada conformedemonstrado na reta tracejadamar-cada com a letra a), e cincomedidas no nvel da papila drmi-ca (conforme demonstrado com a

letra b). Da mesma forma, foramfeitas 10 medidas ao longo daderme em cada amostra de pele,sendo cinco medidas na papiladrmica (conforme demonstradocom a letra A), e cinco medidas no nvel da crista epidrmica (con-forme demonstrado com a letra B) at o limite da derme com a hipo-derme (representada pelo limite inferior da figura). As mdias a-rit-mticas das 10 medidas da epiderme ou da derme por amostra foramutilizadas para o cl-culo da mdia de cada grupo. A extenso da super-fcie de contato epidermo-drmica foi esti-mada pela soma das medi-das realizadas ao longo de 20mm de comprimento de cada prepara-dohistolgico, pelo posicionamento da ocular milimetrada tangencial-mente s irregularidades da borda epitlio-conjuntiva conformedemonstrado nas retas marcadas com os algarismos 1 e 2.

Graph 1: Diagram illustratingthe method used to analyze themorphometry of the epider-mis,dermis and dermoepidermalinterface. In each skin sample, 10measurements were made of theepidermis interface, of which fivewere at the epidermal ridge level(positioning the ocular lens withmillimetric grid as demonstratedin the line marked with the lettera), and five measurements at thepapillary dermis level, as demon-strated with the letter b). In the

same manner, 10 measurementswere made along the dermis ofeach skin sample, of which fivewere at the papillary dermis level(as demonstrated with the letter

A), and five measurements at the level of the epidermal ridge (asdemonstrated with the letter B) up to the limit of the dermis with thehypodermis (represented by the lower limit of the figure). The arith-metic means of the 10 measurements of the epidermis or dermis persample were used to calculate the mean for each group. The exten-sion of the dermoepidermal interface was estimated by the sum ofthe measurements taken along the 20mm length of each histologicalsample, by posi-tioning the ocular scale tangentially to the irregu -larities of the conjunctival-epithelial margin, as demonstrated bythe lines marked with the algorithms marked 1 and 2.


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calculada uma mdia das medidas da espessura da epi-derme e da derme, utilizada ento para obteno damdia de cada grupo. A estimativa da juno epidermo-drmica foi analisada, medindo-se a extenso da superf-cie de contato, ao longo de 20mm de comprimento, peladisposio de linhas retas, seguindo tangencialmente asirregularidades da borda epitlio-conjuntiva. Estas medi-das (espessura da epiderme, derme e estimativa da

juno epidermo-drmica) foram realizadas posicionan-do a ocular contendo uma reta milimetrada nas posiesilustradas na grfico 1.

As fibras elsticas foram estudadas pela tcnicade Van Gieson-elastina, fazendo-se ento uma anlisequalitativa do componente elstico reticular nas amostrasde pele, considerando sua distribuio, disposio e inte-gridade.

A autofluorescncia foi realizada nos cortes cora-dos em H&E da pele normal do abdmen, utilizando-se

um microscpio de fluorescncia da marca Leica,operando com luz transmitida. A fluorescncia doscortes corados em H&E foi examinada porexcitao/emisso de luz ultravioleta e pelo uso de filtrosde barreira 420/530 para fluorescncia verde, seleciona-dos por causa do aumento na qualidade da resoluo,como descrito por Carvalho et al.29

Anlise EstatsticaOs achados morfomtricos foram avaliados utilizan-

do o teste de anlise de varincia ANOVA, seguido peloteste de Bonferroni. O valor de p


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the epidermis in senile skin and an absence of a compact

arrangement of keratinocytes, especially along the

Malpighian strata. Also a disorganized arrangement and a

flattening of the basal cells were observed, with a lessened

accumulation of melanosomes and a lower density of

melanocytes in the senile group (Figures 1B and 3B) whencompared with the young group (Figures 1A and 3A) or the

middle-aged (data not shown). Furthermore, a reduction was

detected in the sinuosity of the area covered by the epidermis

along the length of the dermic surface, revealing a coarse li-

near disposition of the dermoepidermal interface (Figures

1B and 2B) when compared with that of the young group

(Figures 1A and 2A). The basal cell membrane appeared to

pele senil e ausncia do arranjo compacto dos queratinci-tos, especialmente ao longo dos estratos de Malpighi. Almdisso, observaram-se um arranjo desorganizado e achata-mento das clulas basais, com menor acmulo demelanosomas e menor densidade de melancitos no grupo

senil (Figuras 1B e 3B) quando comparado com o grupojovem (Figuras 1A e 3A) ou intermedirio (dado nomostrado). Detectou-se ainda reduo da sinuosidade dotrajeto da epiderme ao longo do comprimento da superfciedrmica, ilustrado por uma disposio grosseiramente lin-ear da juno epidermo-drmica (Figuras 1B e 2B) quandocomparado com o grupo jovem (Figuras 1A e 2A). A mem-

brana basal apareceu mais bem definida na pele senil, con-

Grfico 2: Efeito do processo de envelhecimento na espessura da epiderme e derme no grupo jovem (at 20 anos), grupo intermedirio(20-60 anos) e no grupo idoso (acima de 60 anos). As medidas foram feitas em 10 diferentes locais, cinco nas papilas drmicas, e cinco

nas cristas epidrmicas, utilizando-se uma ocular histomtrica (Leitz Wetzlar Ger-many Periplan GF x10) e uma objetiva de ampliao x10

para a derme e de ampliao x40 para epiderme. As barras representam mdia erro padro da espessura (mm) nos grupos estudadosem relao epiderme (A) e derme (B) pelo teste ANOVA Bonferroni. / Graph 2: Effect of the aging process on the thickness of the epi-dermis and dermis in the young group (up to 20 yrs), Middle-aged group (20-60 yrs) and in the Elderly group (over 60 yrs). The meas-urements were taken at ten different sites, of which five at the level of the pap-illary dermis and five at the epidermal ridge level, usinga histometric ocular lens (Leitz Wetzlar Germany Periplan GF x10) and a 10X objective lens and 40x amplification for the epidermis.The bars represent the mean and standard error of the thickness (mm) in the groups in relation to the epidermis (A) and dermis (B)

using the ANOVA Bonferroni test.

* p


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Figura 1: Espcimes depele dos grupos jovem (A)

e idoso (B) corados pelotricrmio de Van Gieson-elastina, x200, em que asfibras elsticas so obser-

vadas em preto. Note-se aclara fragmentao das

fibras elsticas ao longo daderme com o envelheci-

mento. Na derme superfi-cial, o aparelho elsticoperdeu quase completa-

mente sua disposio verti-cal na pele senil

Figure 1: Skin specimensfrom the young (A) andelderly groups (B) usingVan Gieson-elastintrichrome stain, x200, inwhich the elastic fibers arevisualized in black. Notethe clear fragmentation of

the elastic fibers along thedermis with aging. In thesuperficial dermis, theelastic apparatus hasalmost completely lost itsvertical disposition in theaged skin.



forme observao pelo acmulo de fluorescncia(Figura 3B - seta).

Derme (aparelho colgeno-elstico)Em toda extenso da derme do grupo senil foi detecta-

da fragmentao acentuada das fibras elsticas coradas emnegro pela colorao de fucsina-resorcina de Weigert (Figura1B), em contraste com o aspecto contnuo das fibras elsticasdos espcimes do grupo jovem (Figura 1A). As fibras elsticas,nos preparados de pele do grupo dos idosos, apresentavam-semais frouxamente dispersas e com uma diminuio noentranamento em relao s fibras colgenas, conformedemonstrao pelo contraste fluorescente diminudo (Figura3B). Alm disso, ao longo das rasas papilas drmicas, foi con-

firmada a deficincia do mecanismo de ancoragem em nguloreto das fibras elsticas, ao longo do contorno em campnulado pice papilar nos preparados dos indivduos idosos (Figuras1B e 3B) em contraste com o arranjo das fibras elsticas dosespcimes do grupo jovem (Figura 1A). No grupo senil, osfeixes colgenos estavam menos compactados e ondulados naregio mdia da derme (Figuras 1B* e 3B*), e o aparelhocolgeno-elstico reticular mostrou-se mais susceptvel dis-

perso. Contudo, um arranjo mais compacto e espesso do apar-

be better defined in senile skin, judging by the visibility of the

accumulation of fluorescence (Figure 3B - arrow).

Dermis (elastic-collagen apparatus)

Throughout the extension of the dermis in the senile

group marked fragmentation of the elastic fibers was detected;

these were dyed black by Weigert's stain for elastin (fuchsin and

resorcin) (Figure 1B). This was in contrast with the continuous

aspect of the elastic fibers of the specimens from the young

group (Figure 1A). Elastic fibers, in the preparations of skin of

the elderly group, were more loosely dispersed and less inter-

laced in relation to collagen fibers, as was demonstrated by a

reduced fluorescent contrast (Figure 3B). Besides this, it was

found that among the shallow dermal papillae there was a defi-

ciency in the anchorage mechanism. This was confirmed by theright angle of the elastic fibers along the outline of the papillar

apex in the preparations from elderly individuals (Figures 1B

and 3B) in contrast with the arrangement of elastic fibers of

specimens from the young group (Figure 1A). In the senile

group, collagen bundles were undulated and less compacted in

the area in the middle of the dermis (Figures 1B* and 3B*), and

the collagen-elastic reticular apparatus was shown to be more

susceptible to dispersion. Nevertheless, a more compact and

Figura 2: Espcimes depele corados por H&E,

mostrando autofluorescn-cia na derme superficial e

mdia nos grupos jovem(A) e idoso (B), x200.

Notem-se a reduo con-sidervel do contrastefluorescente na dermemdia (asterisco) e um

componente fluorescentemais evidente no stio da

membrana basal na pele senil (seta)

Figure 2:Skin specimensstained with H&E, showingautofluorescence at the levelof the superficial and middledermis in the young (A) andelderly (B) groups, x200.Note the con-siderablereduction of the fluorescentcontrast in the middledermis (asterisk) and afluores-cent component moreevident in the site of thebasement membrane in agedskin (arrow)

A B

A B

**


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thick arrangement of the collagen apparatus was seen in the

deep dermis of the senile group, as illustrated by the increased

acidophilic coloration (Figure 2B). In the elderly group, the

superficial dermis presented a reduction in its cellularity andextension of the papillar microvasculature, as revealed by the

discreet decline of local fluorescence (Figure 3B).

DISCUSSION

The present study, using the skin of cadavers, docu-

mented the histological alterations occurring during the

aging process. Techniques of histomorphometry and auto-

fluorescence were utilized.

A significant reduction of the thickness of the epi-

dermis and dermis was observed in the skin of the elderly,

as shown by the results of histomorphometry and qualita-

tive analysis applied to preparations dyed by several me-thods. This finding was similar to that reported by other

authors.30,31It is important to consider that some structural

alterations of the skin are inherent to the aging process,

while others are related to sun exposure, environmental

influences, levels of nutrition or alterations in the state of

health, such as endocrinal diseases. It is also necessary to

take into account the differences related to the area of the

body studied, especially regarding the thickness of the skin.

The results obtained by the authors, in relation to the skin

of the abdomen in the young group, were similar to those

described by Shuster et al.30 These authors, using skin of theforearm, also detected a decrease in thickness of the skin

with advancement of age. The results of the present workshow that the reduction of the thickness of the epidermis

and dermis are a characteristic of the last decades of life,

demonstrated by an evident absence of statistical differen-

ce between the morphometric values in the skin of young

individuals and that of the middle-aged. Similar findings

were reported by Shuster et al.30for female individuals.In several ways, the flattening of the papillar dermis

seems to occur progressively throughout life, according to

qualitative observation of the histological preparations

studied in this work (data not shown for the middle-aged

group). In addition, there is a reduction that is statistically

elho colgeno pode ser visto na derme profunda do gruposenil, ilustrado pela crescente colorao acidoflica (Figura2B). No grupo senil, a derme superficial exibiu reduo em

sua celularidade e extenso em ala da microvasculatura papi-lar, revelada pelo discreto declnio da fluorescncia local(Figura 3B).

DISCUSSOO presente estudo documentou as alteraes histol-

gicas da pele de cadveres durante o processo de envelhe-cimento, mediante estratgias de histomorfometria e auto-fluorescncia. Observou-se reduo significativa da espes-sura da epiderme e derme na pele de idosos, ilustrada pelosresultados histomorfomtricos e anlise qualitativa dos

preparados corados por diversos mtodos. Esse achado foi

similar ao encontrado por outros autores.

30,31

importanteconsiderar que algumas alteraes estruturais da pele soinerentes ao envelhecimento, enquanto outras esto rela-cionadas exposio ao sol, influncias ambientais, graude nutrio ou alteraes do estado de sade, como doenasendcrinas. Cabe tambm levar em conta as diferenasrelacionadas regio do corpo estudada, especialmente noque diz respeito espessura da pele. Os resultados obtidos

pelos autores, em relao pele do abdmen no grupojovem, foram semelhantes aos descritos por Shuster et al.30

Esses autores, utilizando pele do antebrao, tambm detec-taram diminuio na espessura da pele com o avanar daidade. Os resultados do presente trabalho mostram que a

reduo da espessura da epiderme e derme foi uma carac-terstica das ltimas dcadas de vida, evidncia demons-trada pela ausncia de diferena estatstica entre os valoresmorfomtricos na pele de indivduos jovens e de idadeintermediria. Achados semelhantes foram encontrados porShuster et al.30para indivduos do sexo feminino.

De forma diversa, o aplanamento da derme papilarparece ocorrer progressivamente ao longo da vida, con-forme observao qualitativa dos preparados histolgicosestudados neste trabalho (dados no mostrados para ogrupo intermedirio), bem como pela reduo j estatisti-camente significante entre os grupos jovem e inter-



Figura 3: Espcimes depele dos grupos jovem

(A) e idoso (B) coradospor H&E, x100. No-tem-

se o achatamento pro-gressivo da juno epider-mo-drmica com o envel-hecimento e a reduo da

acidofilia na derme mdia(asterisco), refletindo a

reduo da densidade defibras colgenas.

Figure 3:Skin specimensfrom the young (A) and eld-erly (B) groups, stained withH&E, x100. Note the progres-sive flattening of thedermoepidermal interfacewith aging and there-duction of the acidophil-

ia in the middle dermis(asterisk), reflecting thereduction in the den-sity ofthe collagen fibers.

A B


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in the reticular dermis as a function of aging, leading to a

predominant horizontalization, following a linear tendency.19

The compromising of the superficial and intermediate colla-

gen and of the structure of elastic tissue could thereby con-

tribute to the picture of ptosis and of wrinkling that charac-

terizes old age so well. In agreement with previous works,35

this research also identified the increase of autofluorescence

in the basal dermoepidermal membrane of senile skin, which

could be explained by the growing deposit of a fluorescent

component and by the increase of its thickness with age. All

of which further reinforces the premise of a deficiency in the

turn over of collagen.34

CONCLUSION

Using morphometric techniques and qualitative

analysis of histological preparations stained by the various

methods associated with autofluorescence techniques, the

present study showed: 1) significant reduction of the thick-

ness of the epidermis and dermis in individuals over 60 yearsof age, suggesting that these parameters do not decrease in a

continuous way, but decrease considerably in the last

decades of life; 2) progressive reduction of the der-moepi-

dermal contact surface throughout life, associated with the

loss of distribution in the elastic fiber network and its pro -

gressive fragmentation; 3) that autofluorescence is a useful

method for analysis of the ultra-structural changes in rela-

tion to aging, because it is an important tool for the detailed

study of the complex disposition of the elastic network and its

spatial relationship with collagen. It clearly reveals the

reduction of the interlacing of the branches of elastic fibers

around bundles of collagen, specific regional alterations ofcompacting and the disposition of collagen in the basal

membrane and its thickening during the aging process. q

a uma predominante horizontalizao, seguindo umatendncia linear. 19 O comprometimento do colgeno super-ficial e intermedirio e da estrutura do tecido elstico pode-ria contribuir, dessa forma, com os quadros de ptose e deenrugamento to bem caracterizados na velhice. De acordocom dados anteriores,35 no presente trabalho foi tambmidentificado o aumento da autofluorescncia na membrana

basal epidermo-drmica da pele senil, o que poderia serexplicado pelo crescente depsito de um componente fluo-rescente e pelo aumento de sua espessura total com a idade,o que refora ainda mais a premissa do turn overdeficientedo colgeno.34

CONCLUSOUtilizando tcnicas morfomtricas e anlise qualita-

tivas de preparados histolgicos corados por diferentesmtodos associados a tcnicas de autofluorescncia, o pre-sente estudo mostrou: 1) reduo significativa da espessura

da epiderme e derme de indivduos aps os 60 anos deidade, sugerindo que esses parmetros no decrescem deforma contnua, mas decrescem consideravelmente nas lti-mas dcadas de vida; 2) reduo progressiva da superfciede contato epiderme-derme ao longo da vida, associada

perda da distribuio em rede das fibras elsticas com suaprogressiva fragmentao; 3) que a estratgia da autofluo-rescncia, para anlise das mudanas ultra-estruturais emrelao ao envelhecimento, importante ferramenta para oestudo detalhado da complexa disposio da rede elstica esua relao espacial com o colgeno, mostrando reduo doentranamento dos ramos das fibras elsticas em torno dos

feixes de colgeno, alteraes regionalmente especficas dacompactao e da disposio do colgeno e espessamentoda membrana basal com o envelhecimento. q

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