Hyperprolactinemia induced histological and ...

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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 ...
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.

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Key words: Hyperprolactinemia, Metoclopramide, Thyroid gland, Histology, Intermediate filaments, Immunostain vimentin, Mice

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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

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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

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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

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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

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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