number of goblet cells and enterocytes in the small intestine of

number of goblet cells and enterocytes in the small intestine of

4
9
G
O B L E T - C (2002)
E L L S - A N47/3-4:
D - E N T E 49-57
ROCYTES-OF-SOREX-ARANEUS
Zoologica
Poloniae
49
NUMBER OF GOBLET CELLS AND ENTEROCYTES
IN THE SMALL INTESTINE OF SEXUALLY IMMATURE
MALES AND FEMALES OF SOREX ARANEUS L.
B OGDANA W ILCZYÑSKA
AND
M ARTA J AROSZEWSKA
Department of Histology and Embriology of Vertebrates, Nicolas Copernicus
University, 87-100 Toruñ, ul. Gagarina 9,
Abstract. The number of goblet cells and enterocytes as well as the height of the
enterocytes forming the epithelial lamina of the mucosa in the small intestine were determined in young males and females of Sorex araneus L. The material included small
intestines of 7 males and 9 females of S. araneus in the first calendar year of their
lives. The intestine was divided into three fragments: anterior, mid and posterior. The
number of goblet cells per circumference of the villous longitudinal section was 7.11±1.014;
8.01±1.221; 12.90±2.934 (males) and 6.46±1.139; 8.45±1.921; 12.02±3.541 (females) in
the consecutive fragments of the small intestine. The number of enterocytes per circumference of the villous longitudinal section for the males was similar in the anterior
(151.55±38.144) and mid (l60.l4±30.613) fragments of the intestine and higher than in the
posterior fragment (139.17±26.486). Likewise, the corresponding values for the females
are identical in all the three fragments, reaching c. 195.79 enterocytes. The ratio of the
number of enterocytes to the number of goblet cells in both sexes was the highest in the
anterior fragment of the intestine: 20.26±3.572 (males) and 31.15±7.352 (females). The
height of enterocytes decreased along the small intestine, with that in males reaching
21.19±2.523 µm (anterior fragment) and 16.77±3.127 µm (posterior fragment); in females, these values ranged from 16.14±1.657 µm to 15.30±2.126 µm, respectively.
INTRODUCTION
The common shrew S. araneus was subject to a number of studies concerning its biology (D EHNEL , 1949; K UBIK , 1951; B OROWSKI et al., 1952;
S ERAFIÑSKI , 1955; P UCEK , 1960; S KOCZEÑ , 1970; B UCHALCZYK , 1972). Some
studies dealt with seasonal changes in the structure of the organs, the skeletal
50
B.-WILCZYÑSKA-AND-M.-JAROSZEWSKA
50
system in particular (D ZIER¯YKRAJ -R OGALSKA , 1952; B AZAN , 1953; C ROWCROFT
et al., 1959; B UCHALCZYK et al., 1964; P UCEK , 1965, 1970; P UCEK M. 1965;
H YVÄRINEN , 1969, 1968). A number of authors pointed to age-dependent-changes
in the structure of the internal organs (F ONS et al., 1984; P UCEK , 1970; S IUDA ,
1964; B IELAK et al., 1960).
There are scarcely any studies on the structure of the alimentary canal in
relation to the food taken by the common shrew. The food consists mainly of
insects (over 90% of food contents) as well as other invertebrates such as
snails, myriapods, young mammals, and small frogs (K OWALSKI , 1964). It is
clear that the alimentary canal of the shrew must be adapted to digesting protein-rich food, which additionally contains much chitin per unit volume. The
studies of M YRCHA (1967) and W ILCZYÑSKA (1996) define a relationship between the histological structure of the esophagus and stomach and the kind of
food taken.
In order to complete the data confirming the relationship between the
food kind and the histological structure of the segments of the alimentary
canal, the epithelium from the small intestine of the common shrew was studied in detail. The number of absorptive cells (enterocytes) as well as of goblet
cells producing epithelium were assessed. Changes in the structure of the
epithelium of the small intestine, which take place throughout the shrew's life,
constitute an interesting aspect here. Consequently, the first stage of the studies was conducted on the small intestine of sexually immature males and females with the body mass of 7-8.8 g. The shrews of this mass, caught in the
summer months, are the heaviest among the individuals born every year and
are during the "stage of relative summer stability" in a physiological sense.
Afterwards, the "autumn regress" takes place in relation to the body size and
the mass of the inner organs (D EHNEL , 1949; K UBIK , 1951; B OROWSKI et al.,
1953; P UCEK , 1965). In the spring, these individuals called wintering ones
(D EHNEL , 1949) become sexually mature and start their intense reproduction.
MATERIAL AND METHOD
The small intestine of the sexually immature males (7) and females (9)
of the common shrew (S. araneus) constituted the material. Their body mass
ranged from 7.0 to 8.8 g (Table l). The animals were caught between July and
August 2000 in Warmiñsko-Mazurskie voievodship.
The removed small intestine was kept for 3 days in a mixture of 10%
formalin solution with 75% ethanol in the ratio 20:1. Then, they were kept for
a month in 4% formalin solution. The intestine was divided into three equal
fragments: anterior, mid, and posterior. The length of consecutive fragments
was measured on drawings made in stereo microscope equipped with the drawing apparatus. The sum of the lengths of consecutive fragments equaled the
total length of the small intestine (Table 1).
51
GOBLET-CELLS-AND-ENTEROCYTES-OF-SOREX-ARANEUS
51
Table 1
Characteristics of the examined shrews
Animal
No
l
2
3
4
5
6
7
8
9
Mass
[g]
7.0
7.1
7.4
7.5
7.6
7.6
8.0
Mean±SD 7.5±0.34
males
Body length
Intestine
[mm]
length [mm]
Mass
[g]
females
Body length
Intestine
[mm]
length [mm]
45.7
62.0
52.6
62.9
66.7
62.0
61.4
9.08
11.65
8.26
11.16
12.17
11.68
10.63
7.2
7.3
7.3
7.5
7.6
7.8
8.0
8.5
8.8
64.0
59.7
56.3
51.7
64.0
56.2
63.0
57.5
61.3
8.89
8.16
9.06
11.44
11.00
14.03
8.81
8.58
7.39
59.0±7.26
10.66±1.46
7.8±0.56
59.3±4.73
9.71±2.08
Histological processing of the material followed the routine protocol
for electron microscopy, using spurr. The blocks were cut perpendicularly to
the long axis of the segment into sections 1-2µm thick, stained with methylene blue with azure II on borax.
The height of intestinal villi from their base to the top was measured in
light microscope with calibrated eye-piece. Along the circumference of the
vertical section through the villi, both goblet cells and enterocytes were counted
and the ratio of the enterocytes to the goblet cells was estimated.
The measurements were taken individually for each intestinal fragment.
Both arithmetical mean and standard deviation were calculated. The significance of the differences between the data from the consecutive fragments was
estimated, with the test for small, untied samples.
RESULTS
The villi in all the small intestine were found to be higher in the males
compared to females. Their height was 332.30±73.164 µm (males) and
310.85±98.755 µm (females) in the anterior fragment of the small intestine,
364.65±90.665 µm (males) and 316.66±44.269 µm (females) in the mid fragment (Table 2). These differences are statistically insignificant. In the posterior fragment of the intestine the height of the villi was similar for both sexes
and amounted to 305.09±71.028 µm (males) and 300.30±18.564 µm (females).
The number of enterocytes along the circumference of the vertical section through the villi was smaller in the males than in the females. There were
151.55±38.144 enterocytes (males) in the anterior fragment of the intestine
52
B.-WILCZYÑSKA-AND-M.-JAROSZEWSKA
52
Table 2
Structural proportions of the mucosa membrane of the small intestine of
the young males and females of the common shrew
Fragment of
small intestine
Height of
villi [µm]
Height of
enterocytes
[µm]
No of
enterocytes
along
circumference of
vertical
section of
villi
No of goblet
cells along
circumference of
vertical
section of
villi
No of
enterocytes
per number
of goblet
cells
7.11±1.014
8.01±1.221
12.90±2.934
20.26±3.572
19.09±4.687
10.52±3.015
6.46±1.139
8.45±1.921
12.02±3.541
31.15±7.352
24.18±5.814
17.99±10.902
males
anterior
mid
posterior
332.30 ±73.164
364.65 ±90.665
305.09 ±71.028
21.19±2.523
18.11±1.766
16.77±3.127
151.55±38.144
160.14±30.613
139.17±26.486
females
anterior
mid
posterior
310.85 ±98.755
316.66 ±44.269
300.30 ±18.564
16.14±1.657
18.29±3.068
15.30±2.126
200.92±54.841
195.99±22.401
190.48±47.158
and 200.92±54.841 (females). The difference was statistically insignificant.
In the mid fragment the number of enterocytes amounted to 160.14±30.613
(males) and 195.99±22.401 (females) (p≤0.1), whereas in the posterior fragment it was 139.17±24.486 and 190.48±47.158, respectively.
In both sexes the number of mucous cells in the epithelial lamina of the
intestine increased along the intestine. In the consecutive segments of the
intestine, these values were similar for both sexes. In the anterior fragment
the number of the mucocytes was 7.11±1.014 (males) and to 6.46±1.139 (females); in the mid fragment 8.01±1.221 (males) and 8.45±1.921 (females);
and 1.90±2.934 (males) and 12.02±3.541 (females) - in the posterior.
In both sexes the difference in the number of mucous cells between the
anterior and posterior fragments was significant (p≤0.01). In the males the
difference between the mid and posterior fragments was also significant (p≤0.05).
The cells were randomly scattered among enterocytes in all the fragments of
the small intestine. They were of characteristic shape, reflected in their name
- goblet cells. Sometimes, their small accumulations could be seen only at the
base of the villi.
The ratio of the number of enterocytes to the number of goblet cells
decreased along the intestine in both sexes, being smaller in the males in all
the intestinal fragments. This ratio amounted to 20.26±3.572 (males) and
31.15±7.352 (females) in the anterior fragment. The difference was statistically significant (p≤0.05). The corresponding values in the mid fragment of
53
GOBLET-CELLS-AND-ENTEROCYTES-OF-SOREX-ARANEUS
53
the intestine were 19.09±4.687 (males) and 24.18±5.814 (females), whereas
in the posterior fragment they were 10.52±3.015 and 17.99±10.902 respectively. In these fragments the difference between males and females was statistically insignificant. By contrast, the differences in the values of this ratio
between the fragments of the intestine were significant in the following cases:
between the anterior and posterior fragments (p≤0.01) and between the mid
and posterior fragments (p≤0.05) in males, and between anterior and posterior fragments (p≤0.05) in females.
In both sexes, the height of enterocytes gradually decreased along the
intestine, with the enterocytes being higher in the anterior intestine fragment
in males compared to females. Their height amounted to: 21.19±2.523 µm and
to 16.14±1.657 µm, respectively. The difference was statistically significant
(p≤0.01). In the next fragments of the intestine the height of enterocytes was
similar for males and females, amounting to 18.11±1.766 µm (males) and
18.29±3.068 µm (females) in the mid fragment, and to 16.77±3.127 µm and
15.30±2.126 µm in the posterior fragment respectively. Only in the males the
height of enterocytes varied between the anterior and mid fragments (p≤0.01)
as well as between the anterior and posterior fragments (p≤0,05).
DISCUSSION
The results of the studies showed differences in the structure of the
epithelial lamina and the height of the villi between the consecutive fragments
of the small intestine of sexually immature males and females of the common
shrew.
In both sexes the villi were higher in the first two fragments of the
intestine (anterior and mid ones) than in the posterior fragment. The differences are of 16.3% (males) and of 5.4% (females). This fact conforms to the
rule stating that in the parts of the small intestine where food absorption is
the most intense, the villi are highest, i.e. with the biggest absorptive area
(K ONTUREK , 1985).
In these fragments of the small intestine in both sexes the number of
absorptive cells (along the circumference of the vertical section through the
villi) was also higher. There were differences between males and females. The
number of enterocytes was considerably smaller in the males. In the females
the number of enterocytes in the initial fragment was by 49.37 higer than in
males; in the mid fragment - by 35.85 more; and by 51.31 more in the posterior fragment. It results from the fact that enterocytes in the epithelial lamina
of the small intestine of females are considerably narrower and smaller than
those in males. The height of the villi is identical for both sexes, therefore,
the entire absorptive area of the villi (formed by the top part of enterocytes)
is the same for both sexes. The number of enterocytes along the circumference of vertical section of the villi was found to change directly in proportion
to their heights.
54
B.-WILCZYÑSKA-AND-M.-JAROSZEWSKA
54
The number of the goblet cells in both sexes increases almost twofold
from the anterior to the posterior fragment of the intestine (1.8 times). The
further the intestinal fragment, the more intense the secretion of mucus covering its internal surface. The presence of the mucus facilitates transport of
food items as well as indigestible substances towards the large intestine. The
mucus of the small intestine, especially in its posterior fragment, enters in
contact with a great amount of solid food. The presence of the increased
number of mucus-producing cells maximally decreases the possibility of damaging the mucous membrane by the chitin present in the food of the common
shrew.
The animals were caught according to permission of Ministry of the
Environment no. DLOPiKog.-4201/262/00 from 2000 year.
LICZBA KOMÓREK KUBKOWYCH I ENTEROCYTÓW W JELICIE
CIENKIM NIEDOJRZA£YCH P£CIOWO SAMCÓW I SAMIC RYJÓWKI
AKSAMITNEJ SOREX ARANEUS L.
STRESZCZENIE
Przeprowadzone badania mia³y na celu okreœlenie liczby komórek kubkowych
i enterocytów oraz wysokoœci enterocytów buduj¹cych blaszkê nab³onkow¹ b³ony
œluzowej jelita cienkiego m³odych samców i samic ryjówki aksamitnej. W tym
celu pobrano jelito cienkie od 7 samców i 9 samic ryjówki aksamitnej w pierwszym
kalendarzowym roku ich ¿ycia. Jelito podzielono na trzy fragmenty: pocz¹tkowy,
œrodkowy i koñcowy. Stwierdzono, ¿e liczba komórek kubkowych, przypadaj¹ca
na obwód pod³u¿nego przekroju przez kosmki, wzrasta wraz z d³ugoœci¹ jelita
i w trzech jego czêœciach jest jednakowa dla obu p³ci. Wynosi ona w pocz¹tkowym
fragmencie 7,11±1,014 (samce) i 6,46±1,139 (samice), w œrodkowym 8,01±8,1,221
(samce) i 8,5±1,921 (samice) i odpowiednio 12,90±2,934 i 12,02±3,541 w koñcowym fragmencie. Zarówno u samców jak i u samic ró¿nica w liczbie komórek
miêdzy pocz¹tkowym i koñcowym fragmentem jelita jest istotna statystycznie
(p≤0,01). U samców liczba enterocytów na obwodzie pod³u¿nego przekroju
przez kosmki jelita cienkiego jest wiêksza i zbli¿ona w pocz¹tkowym
(151,55±38,144) i œrodkowym (160,14±30,613) fragmencie jelita i mniejsza
w koñcowym (139,17±26,486). Analagiczne dane dla samic s¹ jednakowe we
wszystkich trzech fragmentach i wynosz¹ œrednio: 195,79 enterocytów. Stosunek
liczby enterocytów do liczby komórek kubkowych zarówno u samców jak
i u samic jest najwy¿szy w pocz¹tkowej czêœci jelita i wynosi: 20,26±3,572
u samców i 31,15±7,352 u samic. Ró¿nica w wartoœci tego wspó³czynnika
miêdzy samcami i samicami jest istotna statystycznie tylko w pocz¹tkowym
fragmencie jelita (p≤0,05). Wysokoœæ enterocytów maleje wzd³u¿ jelita cienkiego
i wynosi u samców w pocz¹tkowym fragmencie jelita 21,19±2,523 µm,
w œrodkowym 18,11±1,766 µm i w koñcowym 16,77±3,127 µm. Ró¿nica
55
GOBLET-CELLS-AND-ENTEROCYTES-OF-SOREX-ARANEUS
55
w wysokoœci enterocytów miêdzy pocz¹tkowym i koñcowym fragmentem jelita
jest istotna statystycznie (p≤0,05) jedynie u samców. U samic wartoœæ ta wynosi
odpowiednio 16,14±1,657 µm, 18,29±3,068 µm 15,30±2,126 µm. Miêdzy samcami
i samicami ró¿nica w wysokoœci enterocytów jest istotna statystycznie tylko
w pocz¹tkowym fragmencie jelita (p≤0,01).
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