Splenomegaly in Antarctic fish Cabeçuda

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Pesquisa Antártica Brasileira (2012) 5: 171-174
(Brazilian Antarctic Research)
ISSN 0103-4049
http://vega.cnpq.br/pub/doc/proantar/
Splenomegaly in Antarctic fish Cabeçuda Notothenia coriiceps
(Richardson, 1844)
JOSÉ R.M.C. SILVA, IDÉRCIO L. SINHORINI, BERNARD E. JENSCH-JUNIOR,
LEANDRO N. PRESSINOTTI, BRUNO C. VELLUTINI and JOÃO C.S. BORGES
Department of Histology and Embryology, Biomedical Sciences Institute, University of São Paulo,
Av. Prof. Lineu Prestes, 1524, 05508-900 São Paulo, SP, Brazil
ABSTRACT
An enlarged spleen was found after the necropsy of a specimen of the Antarctic fish N. coriiceps, and
described macro and microscopically after inclusion for light microscopy. Sixteen fishes were used to
compare the spleen weight. The spleen of the splenomegalic fish represents 1.44% of the total weight, while
on the others it represented 0.24 ± 0.04%. The increase of the spleen indicates a pathological phenomenon.
Histological study shows an obstruction of the vascular system of spleen and consequent necrosis. This work
shows for the very first time a fish splenomegaly naturally found at Antarctic temperatures.
Key words: Notothenia coriiceps, spleen, pathology, Antarctica.
INTRODUCTION
In the Antarctic environment, where temperatures
are around 0◦ C, we find references of the physiology and the adaptation of fishes to these low temperatures, but there are very few works describing
inflammatory processes in these animals (Borges
et al. 2002, Silva et al.). Despite the intense parasite infestation at the liver (Silva et al. 1998), there
are very few studies describing natural occurring
pathology in these fishes (O’Neill et al. 1987; Silva
et al. 1998). This work describes a natural splenomegaly found in N. coriiceps with a histological
study.
MATERIAL AND METHODS
The necropsy of one Notothenia coriiceps – Cabeçuda (Richardson 1844) showed a splenomegalic
condition. The fish was a female, total length =
34.5 cm, standard length = 30.50 cm, total weight =
Correspondence to: José Roberto M. Cunha da Silva
E-mail: [email protected]
625.00 g and the spleen weight = 9.02 g (Table I).
In order to compare, sixteen fishes were used to
measure the same parameters (total weight =
766.26 ± 154.90, total length = 37.73 ± 2.58,
standard length = 33.66 ± 2.44 and spleen
weight = 1.83 ± 0.42). All fishes were collected
in January-February 2002 in Admiralty Bay, King
George Island, South Shetland Islands (S 62◦ 10,
1680 ; W 058◦ 26, 9590 ). Fishes were kept in fibreglass tanks and acclimatized during one week. The
tanks (2,000 l) were filled with running seawater
(1.0 ± 1.0◦ C) in the Biology Laboratories of the
Brazilian Antarctic Station “Comandante Ferraz”,
where the biometric data and identification, according to Gon and Heemstra, 1990, of these animals
took place.
RESULTS AND CONCLUSIONS
The spleen of the splenomegalic animal as well as
two spleens from the group of 16 fishes were included for light microscopy studies (Fig. 1); the
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JOSÉ ROBERTO MACHADO CUNHA DA SILVA et al.
TABLE I
Biometrical data of the splenomegalic animal and the 16 other control fish.
Sex
Normal Fish (n=16)
SD
Splenomegalic Fish (n=1)
M/F
F
Total
Weight
(g)
766.26
154. 90
625.00
fixations of the spleen were carried out in the
fixative solution of McDowell and Trump, 1976.
Afterwards, the material was dehydrated in 95%
alcohol, and subsequently embedded in Historesin
Leica. Sections of 2 μm were obtained in the biology laboratories of the Brazilian Antarctic station and stained with H.E., fuchsin-toluidin blue
and Romanowsky. The observation and documentation of the slides were carried out in Zeiss Axiomat
photomicroscopes.
Total
Length
(cm)
37.73
2.58
34.50
Standard
Length
(cm)
33.66
2.44
30.50
Spleen
Weight
(g)
1.83
0.42
9.02
Spleen/Total
Weight
(%)
0.24
0.04
1.44
possible to observe a lot of vessels running trough
the capsule, going deeper at the white regions and
at surface of the dark regions.
After the longitudinal division of the spleen,
an internal uncommon cavity could be seen filled
with a colourless liquid (Fig. 2).
Fig. 1 – Spleen from the splenomegalic fish showing a yellowish
region at the surface and the superficial vessels trough the capsule
and two normal ones. There is a yellowish region surface capsule
Fig. 2 – Transversal section of the spleen showing a cavity with
The averaged percentage of the spleen in relation to total weight of the splenomegalic fish was
about six times higher than the others, or 1.44%
for the splenomegalic fish and 0.24 ± 0.04%
minimum = 0.16% and maximum value = 0.33%
for the others fishes (Table I).
The capsule of the spleen was modified and
irregular with many asymmetric protuberances
when compared with normal spleen. The colour
varies from dark red to yellowish regions while the
normal spleen is homogeneously dark red.
At the dorsal region there was an amorphous
yellowish mass under the capsule (Fig. 1), and it is
The histology showed that the yellowish regions were mainly composed by necrotic tissue
(Fig. 3) with mononuclear inflammatory infiltrate
predominantly at the central region (Fig. 4). The
periphery of the organ contained non-altered morphology parenchyma with many lymphocytes, erythrocytes and very delicate connective tissue trabeculae (Fig. 5). The blood vessels present at the
periphery may indicate a neovascularization as part
of the inflammatory process. They are larger in diameter compared to the normal spleen sinusoidal
capillaries.
The yellowish regions correspond to the
(scale bar in mm).
Pesq Antárt Bras (2012) 5
colourless fluid and the hilus (scale bar in mm).
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SPLENOMEGALY IN ANTARCTIC FISH
Fig. 3 – Histological transversal section of the splenomegalic
spleen showing the capsule and subjacent regions including the
necrotic region (scale bar = 200 μm).
regions. This layer is composed by many elongated
cells (fibroblasts like), suggesting that the splenomegaly was not recent.
The increase of the spleen size is evident, about
six times the normal spleen weights, clearly indicating a pathological phenomenon. The characteristics
described above points out for an obstruction of the
vascular system of the spleen and consequent lack
of blood flow and necrosis, but not enough to let the
fish die. This work shows for the very first time a
fish splenomegaly naturally found at Antarctic temperatures.
ACKNOWLEDGMENTS
We thank CNPq for the financial support from grant
490104/00-1, 68.0047/00-0 and 48.0262/00-4,
PROANTAR/SECIRM and the logistic support
given by the Brazilian Navy. We also thank the
‘Grupo Base Único’ from the Comandante Ferraz
Brazilian Antarctic Station for their general help.
One of the authors (Vellutini, B. C.) had an ITI
scholarship from CNPq.
Fig. 4 – Histological transversal section of the splenomegalic
spleen showing mononuclear inflammatory infiltrated, at the periphery and in the necrotic area (scale bar = 50 μm).
RESUMO
O objetivo foi estudar uma esplenomegalia encontrada
em fevereiro de 2002 na cabeçuda (peixe antártico)
Notothenia coriiceps (PT = 625 g, CT = 34,5 cm e Cstd.
= 30,5 cm). Após a necrópsia foi removido o baço deste
animal, e de mais 15 peixes normais (PT = 766,26 ±
154,9 g, CT = 37,73 ± 2,58 cm e Cstd. = 34,9 ± 2,44 cm)
para comparação da porcentagem do baço no peso vivo
do animal. A proporção do baço nos peixes normais foi
de 0,24 ± 0,01%, enquanto o peixe com esplenomegalia
apresentou uma porcentagem de 1,44%, ou seja, cerca
de seis vezes maior. A cápsula do baço alterado é irreguFig. 5 – Histological transversal section of the splenomegalic
spleen showing the functional residual parenchyma including
capsule (scale bar = 25 μm).
emerging of the necrotic area described above to
the surface of the spleen. In some regions, there
is a third layer between the central and periphery
lar com inúmeras protuberâncias assimétricas, comparada
aos baços normais. A coloração varia do vermelho-claro
ao vermelho-escuro com regiões esbranquiçadas (padrão
saudável: vermelho escuro e homogêneo). Na região dorsal há uma massa amorfa de aparência amarelada sobre a
cápsula. Podemos observar uma grande quantidade de
vasos que correm pela cápsula sendo mais profundos nas
regiões claras e mais superficiais nas escuras (estes não
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JOSÉ ROBERTO MACHADO CUNHA DA SILVA et al.
aparecem no baço normal). Após um corte transversal
pode ser identificada uma cavidade interna incomum e
relativamente grande preenchida por líquido incolor. A
histologia mostrou que as áreas esbranquiçadas eram
regiões compostas de tecido necrótico, com infiltração
mononuclear predominantemente na região central, en-
quanto na periferia do órgão encontramos uma camada
de parênquima com morfologia inalterada, ou seja, com
grande quantidade de linfócitos, eritrócitos e delicadas
trabéculas de tecido conjuntivo. As regiões esbranquiçadas correspondem a área necrosada que aflora à su-
perfície do órgão. Em algumas regiões, entre as duas
camadas já descritas (central e periférica), encontramos
uma terceira camada, com grande quantidade de célu-
las alongadas com morfologia compatível a fibroblastos,
sugerindo uma cicatrização e indicando que a esplenomegalia não era recente. As características acima, indicam
que houve uma obstrução na rede vascular do órgão, com
consequente isquemia e necrose, sem entretanto levar o
animal a óbito. Este trabalho mostra pela primeira vez
uma esplenomegalia em peixes Antárticos que vivem a
temperaturas próximas a (0◦ C).
Palavras-chave: Notothenia coriiceps, baço, patologia,
Antártica.
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