International Journal of Scientific & Engineering Research, Volume 7, Issue 4, April-2016 ISSN 2229-5518
170
Hyperprolactinemia induced histological and cytoskeletal vimentin alterations in mice thyroid glands Nabila I. El-Desouki*, Mohamed L. Salem, Mohamed Nasef. and Faten M. Abdallah Department of Zoology, Faculty of Science, Tanta University,Tanta 31527, Egypt. Corresponding author: Nabila Ibrahim El-Desouki, Zoology Department, Faculty of Science, Tanta University, Egypt. E-mail:
[email protected] Abstract: The present investigation is planned to demonstrate histological and immunohistochemical detection of vimentin of the thyroid gland of hyperprolactinemic adult male mice (Mus musculus) for different durations by using metoclopramide (MCP). Mice were divided into five groups. Group I: control mice group were injected with saline solution i.p. for 10 weeks, groups II, III, IV and V; mice were treated with MCP i.p. in a dose of 2.2 mg/kg/ b.w daily for different durations 2, 4, 7 and 10 weeks, respectively. The results recorded a significant increase in the body weight of mice groups III, IV and V, and a significant increase in the levels of prolactin hormone of groups IV and V. The thyroid gland of the control mice group stained with H &E demonstrated normal appearance of follicles with normal simple cuboidal cells; each cavity is filled with acidophilic colloid. HPRL groups for 2 & 4 weeks (groups II&III) showed histopathological changes include vacuolation of cytoplasm, fusion of some follicles and others are free from colloids. HPRL groups for 7 & 10 weeks (groups V&IV) illustrated atrophy of follicular cells, flattened of the thyrocytes, interference of many follicles, few colloids appearance and widen between follicles. Additionally, delicate collagen fibers around the follicles and periphery to blood vessels were seen in the thyroid glands of control mice by using azan stain. In HPRL groups (2&4 weeks), the collagen fibers were increased in interfollicular cells and peripheral to blood vessels while in 7&10 weeks groups, the thyroid glands illustrated a reduction of collagen fibers. Weak immunostain to vimentin in the thyroid of control group was expressed. In HPRL III&IV groups for 2 and 4 weeks, intense immunoreactivity to vimentin in the connective tissue periphery to thyrocytes and in the dilated blood vessel walls was expressed. In HPRL groups for 7 and 10 weeks showed decrement of immunoreactivity to vimentin filaments. In conclusion, MCP increased the prolactin hormone and led to histological changes in the thyroid glands that were time– dependent, and finally caused thyrocytes atrophy. MCP also caused pathologically disturbance in the intermediate vimentin filaments. Therefore, MCP should not be used for long duration, and must be used with caution as a therapy.
IJSER
Key words: Hyperprolactinemia, Metoclopramide, Thyroid gland, Histology, Intermediate filaments, Immunostain vimentin, Mice
—————————— ——————————
also plays an essential role in metabolism,
Introduction
regulation of the immune system and pancreatic
U
Prolactin (PRL) is a peptide hormone and is
development [1-4].
one of several hormones that are produced by the
The amount of PRL can be an indicator for
pituitary gland that known as luteotropic hormone
the amount of sexual satisfaction and relaxation.
or luteotropin. The best known for its role is
Unusually high amounts of PRL are suspected to
enabling female mammals to produce milk
be responsible for impotence and loss of libido and
(lactation). Thyrotropin-releasing factor (TRH) has
decrease the levels of sex hormones (estrogen in
a stimulatory effect on PRL release. Most
women and testosterone in men). PRL within the
vertebrates including humans also have the closely
normal reference ranges can act as a weak
related somatolactin. PRL has a wide range of
gonadotropin but at the same time suppresses GnRH secretion [5]. Physiologic levels of PRL in
effects; it is influential over a large number of
males enhance luteinizing hormone-receptors in
functions with over 300 separate actions of PRL
Leydig cells, resulting in testosterone secretion,
having been reported in various vertebrates. PRL
which leads to spermatogenesis [6]. PRL has also a
IJSER © 2016 http://www.ijser.org
International Journal of Scientific & Engineering Research, Volume 7, Issue 4, April-2016 ISSN 2229-5518
171
number of other effects including contributing to
in addition to increasing TSH causes to raise PRL
pulmonary surfactant synthesis of the fetal lungs at
level [14-16]. A study showed the relationship
the end of the pregnancy and immune tolerance of
between subclinical hypothyroidism, HPRL and
the fetus by the maternal organism during
sterility [17], although some studies reported that
pregnancy, delays hair regrowth in mice [7], and
HPRL
promotes neurogenesis in maternal and fetal brains
hypothyroidism [18].
[8&9].
common endocrine disorder of the hypothalamic-
rare
disorder
in
subclinical
Metoclopramide (MCP) was first described 0T
Hyperprolactinemia (HPRL) is the most
is
0T
by Justin-Besançon and Laville in 1964 [19]. It is a medication
pituitary axis. A prolactinoma is the most common
used
mostly
for stomach 0T
0T3
0T3
and
esophageal problems. It is commonly used to 0T3
0T3
0T
0T
0T
cause of chronic HPRL once pregnancy, primary
treat nausea and vomiting, to help with emptying
hypothyroidism, drugs, medical herbs and heavy
of the stomach in people with delayed stomach
metals that elevated serum PRL levels [10]. HPRL
emptying due
may also be the result of disease of other organs
surgery, and to help with gastroesophageal reflux
such as the liver, kidneys, ovaries and thyroid.
disease. It is also used to treat migraine headaches
Some women with polycystic ovary syndrome may
[20]. Common side effects include: feeling tired,
have
0T
0T3
0T3
0T
0T3
3T
0T3
0T
3T
0T
0T
to
0T
0T3
either diabetes or 0T
0T3
0T3
0T
0T3
following
0T
0T3
0T3
0T
IJSER
mildly-elevated
PRL
levels
[11].
diarrhea, and feeling restless. More serious side 3T
3T
HPRL of hypothyroidism is related to several
effects include HPRL and depression. In 2014,
mechanisms. In response to the hypothyroid state,
MCP was one of the top 100 most prescribed
a compensatory increase in the discharge of central
medications in the United States [21]. Therefore,
hypothalamic
hormone
the present study aims to evaluate the effect of
results in increased stimulation of PRL secretion.
hypersecretion of PRL (HPRL) experimentally-
Primary hypothyroidism can be associated with
induced in adult male albino mice (Mus musculus)
diffuse pituitary enlargement, which will reverse
by MCP on the histology and immunostain of
with appropriate thyroid hormone replacement
intermediate vimentin filament alterations of the
therapy [12].
thyroid gland.
thyrotropin
The thyroid 0T
releasing
gland
0T
is
one
of
the
largest endocrine glands in the body, and consists 0T
0T3
0T3
0T
0T
0T3
3T
Materials and Methods U
І- Animal selection and care:
of two connected lobes in the anterior neck, and it
Fifty adult male albino mice (aged 6-8
controls rate of use of energy sources, protein
weeks) weighing 25±2g, were obtained from
synthesis, growth and rate of function of many
Vacsera, Cairo. Animals were housed in plastic
other systems. It participates in these processes by
cage (10 per cage) for one week acclimatization
producing thyroid hormones, the principal ones
under the same condition of temperature and
being thyroxin (T 4 )
triiodothyronine (T 3 ),
natural dark- light cycle. Food and tap water were
which is more active under the influence of TSH
freely available to the animals throughout the
produced by the anterior pituitary, which itself is
experiment. All protocols and procedures adopted
regulated by thyrotropin-releasing hormone (TRH)
for the present investigation were in accordance
produced by the hypothalamus [13]. In fact, TRH
with the approval of the Institutional Animal
0T
0T
0T
0T3
3T
0T
0T3
0T3
3T
0T3
0T
0T3
3T
0T
0T
0T3
3T
0T3
0T3
0T
R
0T
0T
R
and 3T
0T2
0T3
0T2
0T2
R
R
2T
0T2
0T
0T
2T
0T
IJSER © 2016 http://www.ijser.org
International Journal of Scientific & Engineering Research, Volume 7, Issue 4, April-2016 ISSN 2229-5518
172
Ethics Committee of National Research Center and
ethyl alcohol, cleared in xylene, embedded in
in accordance with recommendation of the proper
paraffin wax and sectioned at 5µ thicknesses.
care and use of laboratory animals, regulated by
Paraffin sections were used for the histological
Faculty of Science, Tanta University.
study (H & E and azan stains) [24], and
II- Induction of HPRL:
immunohistochemical avidin- biotin method to express vimentin [25].
HPRL was induced by intraperitoneal (i.p.) injection of MCP obtained from "Sigma Chemicals Co., St. Louis, Mo., USA" [22].
Results U
I) Effect of HPRL on body weight U
III- Experimental design:
Table 1 illustrated mean values of body
The mice were divided into 5 equal groups (10
weight in control group and HPRL groups received
mice / each group). Group I, normal control
2.2 mg/kg/ b.w of MCP intraperitoneally for 2, 4, 7
mice group were injected with saline solution
and 10 weeks. These values were 27.9 ± 0.93,
i.p. daily for 10 weeks. Groups II, III, IV and
23.41 ± 2.82, 29 ± 1.75, 31.23 ± 1.41 and 32.12 ±
V, the mice were treated with MCP i.p. in a
3.71, respectively. Analysis of variance (ANOVA) test showed
dose of 2.2 mg/kg/ b.w daily for different
non-significant increase in body weight of group II
IJSER
durations as 2, 4, 7 and 10 weeks, respectively. IV- Sample collection and serum separation:
At the end of each period of the experiment,
the animals were anaesthetized using diethyl ether,
and then sacrificed. Blood samples were collected
from all studied groups and allowed to clot at room temperature for 30 minutes before centrifugation at 1000 revolutions per minute for 20 minutes and
as compared to group I (P˃0.05); a significant increase in body weight of group III and Group IV as compared to group I (*p