Special Section Histology of normal tissues Original Research Open Access [602524]

Special Section | Histology of normal tissues | Original Research Open Access
Histological effect of ovariectomy and estrogen
replacement on parotid gland of adult albino rat
Dalia A. Mohamed, Heba M. Elnegris* and Rania A. Wahdan
Abstract
Introduction : Many women undergo hormone replacement therapy in order to relief the menopausal and
postmenopausal symptoms. Oral discomfort is common among these symptoms.
Aim of work : This work aimed to study the possible histological changes of parotid gland associated with
ovariectomy and to assess the possible beneficial role of estrogen replacement.
Materials and methods : Thirty healthy adult female albino rats were equally divided into three main
groups. Group I: Served as control that was subdivided into two subgroups; the sham operated (Ca) and
vehicle-treated (Cb). Group II was the experimental group overiectomized (OVX) one. Group III: was treated with 17_-estradiol (E2) (Teikoku Hormone Mfg. Co., Ltd., 50 mg per day) consecutively for 14 days. At the time of sacrifice, the rats were anaesthetized and specimens from parotid of all rats were stained by H&E and Mallory trichrome stains. The percent of collagen fiber and diameter of ducts were measured. Morphometrical results were statistically analyzed. Immunohistochmical staining for Cu, Zn-SOD was also performed to assess the role of estrogen supplementation.
Results : Examination of parotid in OVX group showed different forms of degenerative changes. The acini
appeared irregular and lined with some apoptotic cells. Their cytoplasm contained extensive vacuolations.
Homogenous acidophilic material, cellular infiteration within thick CT septa, dilated ducts with stratification in their lining and congestion of blood vessels were also seen. Positive immunostaining for Cu, Zn-SOD appeared in acinar cytoplasm. Ultrastructurally, rarified dilated RER, electron dence and lucent granules were also seen. Estrogen replacement improved the histological changes in treated group.
Conclusion : Results obtained in this study suggest that estrogen deficiency in postmenopausal women lead to
variable degenerative changes in parotid salivary glands of adult female albino rats with relative limitation of
these changes in estrogen supplemented group.
Keywords : Parotid gland, ovariectomy, ultrastructure, estrogen replacement
© 2015 Elnegris et al; licensee Herbert Publications Ltd. This is an Open Access article distributed under the terms of Creative Commons Attribution License
(http://creativecommons.org/licenses/by/3.0). This permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Introduction
The average woman lives about one-third of her life beyond
menopause and many undergo hormonal replacement therapy
to relieve menopausal symptoms . Oral discomfort is a common
symptom in these women and may be documented as one of
the systemic aspects of menopause [ 1].
In postmenopausal period the endogenic estrogen level
decreases. This is a primary change provides for many charac –
teristic alterations in almost all the body. Estrogen acts through
two intracellular receptor proteins called estrogen receptors
(ER) [ 2]. It was reported that ER present in oral buccal mucosa,
minor salivary glands, parotid and submandibular glands [ 3].The most important and annoying oral affections in menopause
are alteration in taste and burning mouth syndrome (BMS).
BMS refers to a chronic orofacial pain disorder that occurs in
about 1.3 million American women in the postmenopausal
period. Hormonal changes may affect the composition or the
rate of saliva [ 4].
Streckfus et al., [ 5] reported that there was reduction in the
salivary flow of submandibular and sublingual glands with
the increase in age and reduction in the levels of estrogen
production. The ovarian hormones act on the oral mucosa
by specific receptors, which select, recognize, and bind the
hormone to the cell cytoplasm or nucleus. The deficiency of *Correspondence: heba31076@yahoo.com
Department of Histology and Cell Biology, Faculty of Medicine, Zagazig University, Egypt.Journal of Histology & Histopathology
ISSN 2055-091X | Volume 2 | Article 23
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these hormones (estrogen) possibly causes changes in the
oral mucosa at the tissue level, because these hormones in –
fluence the proliferation, differentiation, and keratinization
of the gingival epithelium and stimulate the proliferation of
fibroblasts [ 6].
Sex steroid hormones are known to regulate cell growth,
differentiation and function in reproductive as well as non –
reproductive tissues [7]. Also, these hormones appear to play
a significant role in the physiology of the human oral cavity.
A number of studies suggest that oral soft tissues are sensi –
tive to changes in female sex steroid blood levels. So, some
diseases and disorders of the oral cavity, show a prediction for
women [8], supporting a role for estrogen in disease etiology.
Additionally, it was reported that estrogens are known to
modulate epithelial maturation in classic target organs, and
similarly, the decrease in estrogen levels during menopause
is thought to affect the oral epithelial maturation process,
leading to thin and atrophic epithelium prone to inflamma –
tory changes [ 7].
Oral dryness can lead to considerable difficulty in speak –
ing, eating and tasting, and predispose mucosa to wounds,
abrasion and infection. A number of studies have shown that
hormone replacement therapy (HRT) can relieve this oral
discomfort in postmenopausal women, further suggesting
a role for female sex hormones in the maintenance of oral
tissues [ 9,10].
Apoptosis, i.e., programmed cell death, plays an important
role in homeostasis of the body. Previously, it was reported
that a reduction of estrogen (belongs to female hormones)
could have influence on age-related histological changes in
the female rat parotids induced by apoptosis .One component
of inducing apoptosis is free radical. Recently, it have been
noticed that free radical has an effect on aging.
A living body has superoxide dismutase (SOD), which can
eliminate free radical. SOD decreases with aging progress [ 11].
Together, these observations suggest that estrogens may
play an important role in oral mucosal and salivary gland
physiology. Even though the salivary glands are not classical
targets of female sexual hormones, this study was performed
to analyze the influence of the sex hormones on these glands
as little is known about this relation.
Materials and methods
Thirty Female Sprague–Dawley rats, 3 months in age and approx –
imately 120 g in weight, were used. The animals were housed
in individual cages and received a standard diet and tap water
ad libitum. The room temperature and humidity were main-
tained at 23°C and 60%, respectively. The light cycle was fixed
at 12 h. They were equally divided into three groups; I, II and III.
Group I: was the control (C) that was subdivided into two
subgroups; Ca (sham-operated) and Cb (vehicle-treated)
groups received daily SC injections of sesame oil (0.1ml /day).
Group II: was the experimentally induced ovariectomy (OVX).
Group III: was the experimentally induced ovariectomy and received immediate daily subcutaneous (SC) injections
of 17-estradiol (E2) dissolved in sesame oil (Teikoku Hormone
Mfg. Co., Ltd., Tokyo, Japan) (50 mg per day) consecutively for
14 days (treated) [ 11].
After 1 week acclimatization in the animal house, each
group (10 animals) underwent an operation. The animals were
anesthetized with intraperitoneal injection of pentobarbital
sodium (15 mg/kg body weight) for the surgical procedure.
In the ovariectomized group, small incisions were made
on each flank. The ovaries and their surrounding fat were
externalized and after ligation of the ovarian arteries the
ovaries were removed. The distal ends of each uterine horn
were then returned to the peritoneal cavity and the incisions
were closed with 4-0 nylon sutures. Each rat received an in –
tramuscular injection of 0.1 ml PenicillinG procaine (300,000
unit ml-1, Phoenix Pharmaceutical Inc., St. Joseph, MO) as a
prophylactic measure. The sham-operated group underwent
a similar surgical procedure, exposing the ovaries but replac –
ing them in the same position.
The animals were sacrificed two weeks after the operation
and specimens from right parotid of each animal were fixed
in 10 % neutral formol saline for 24 hours and were processed
to prepare 5 µm thick paraffin sections for haematoxylin and
eosin stain and Mallory trichrom stains [12] Also, parts of the
same specimens were processed for electron microscope
examination [13].
Quantitative morphometric measurements
Serial sections stained with H&E and Mallory’s trichrome were
morphometrically analyzed for detection of diameter of the
parotid ducts; area % of blue stained collagen fibers in the
septa, around duct and blood vessels using Leica Qwin 500
image analyzer computer system (Cambridge, England) at Pa-
thology Department, Faculty of Dentistry, Cairo University. The
image analyzer consisted of a colored video camera, colored
monitor, hard disc of IBM personal computer connected to the
Olympus microscope (CX 41) and controlled by Leica Qwin 500
software. The image analyzer was first calibrated automatically
to convert the measurement units (pixels) produced by the
image analyzer program into actual micrometer units. The
measuring frame of a standard area is equal to 7286, 78μm².
For each parameter ten different non overlapping fields
from ten different specimens were examined in each group.
Cu, Zn-SOD (cupper, zinc superoxide dismutase) immuno-
histochemical study
Deparaffinized sections were incubated in 0.3% H2O2 in metha –
nol for 30 min at room temperature to inhibit endogenous
peroxidase activity. The avidin–biotin–peroxidase complex
method [ 14] was performed as follows. The sections were
treated in 10% normal goat serum for 30 min, and incubated
in anti-Cu, Zn-SOD anti-serum (1.5 mg/ml, Sterssgen) of a
dilution of 1:200 for overnight at 4°C, and then incubated
in biotinylated anti-rabbit IgG solution for 30 min at room

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temperature and the avidin–biotin–peroxidase complex solu –
tion of a Vectastain ABC Kit (Vector Laboratories Inc) for 1 h
at room temperature. All the antibody solutions were diluted
with 0.01 M phosphate buffer saline (pH 7.4). All the sections
were then stained with 3.3 diaminobenzidine containing
0.03% H2O2. We used fixed reaction times for the processing
in all cases. Positive staining was clearly cytoplamic reactivity.
Statistical analysis
The obtained data from morphometrical analysis were sub –
jected to one way analysis of variance (ANOVA) and post hoc
test using Statistical Package for the Social Sciences (SPSS) ver –
sion 11. The P value <0.05, <0.001 and >0.05 were considered
significant, highly significant and non significant respectively.
Results
Light microscopic results
Examination of H&E stained sections showed that control
groups (Ca&Cb) had the same structures. The parenchyma
of parotid gland was formed of serous acini and duct system.
The acini appeared rounded with secretory cells and narrow
lumima. They had basal basophilic nuclei and apical acidophilia.
The intralobular duct had normal structure. Thin connective
tissues appeared around ducts, blood vessels and inbetween the lobules (Figure 1A ). Examination of H&E stained sections of
operated group (II) revealed that most of the acini appeared
irregular with darkly stained nuclei and many vacuoles in their
cytoplasm. They were separated by thickened septa contain –
ing cellular infiltration. Homogenous acidophilic material was
also seen ( Figure 1B ). The interelobular ducts were dilated and
lined by stratified epithelium. Congested blood vessels were
also found ( Figure 1C ). Examination of H&E stained sections
of treated group (III) showed apparent normal appearance
of serous acini and ducts ( Figure 1D ).
Mallory’s trichrome stained sections clarified the occur –
rence of little collagen fibers inbetween the lobules, around
interlobular ducts and blood vessels in parotid gland of group
I (Figure 2A ). While in group II, collagen fibers of extensive
amount appeared in between the lobules and around blood
vessels ( Figure 2B ). Group III revealed moderate amount of
collagen fibers ( Figure 2C ).
Examination of the semithin section of group I revealed the
normal appearance of the acini and intrelobular ducts of the
gland. The acini were lined by pyramidal cells that had basal
vesicular nuclei and apical secretory granules. In between the
lobules, the ducts appeared with normal structure ( Figure 3A ).
While examination of group II showed irregular acini with vari –
able sizes. They had apoptotic nuclei and many vacuoles in their
Figure 1. H&E stained sections.
(A): Control group showing rounded serous acini (S) with narrow luminae. They have basal basophilic nuclei (curved arrow) and apical acidophilia (arrowhead). Note, normal appearance of intralobular ducts (D) and thin septa (CT). (B): Operated group showing irregular acini (S) with darkly stained nuclei (curved arrow)
and cytoplasmic vacuolations (V). Cellular infiltration (f) inside thick connective tissue
(CT) septa is also seen. Notice, homogenous acidophilic material (M). (C): Showing dilated interlobular ducts (D) with stratified epithelial lining (E); prominent thick septa (CT) are also seen. Congestion of blood vessels (BV) is also seen. (D): Treated group showing apparently normal serous acini (S) and intralobular ducts (D) of parotid gland. (Scale bar=20µm).

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containing dilated interlobular ducts. Some of the epithelial lin –
ing of the ducts appeared with darkly stained nuclei ( Figure 3B ).
Treated group examination showed apparent normal serous
and interlobular ducts of parotid gland (Figure 3C ). Immuno –
histochemical stained sections of control group (I) showed
positive cytoplasmic reaction for CU,Zn-SOD ( Figure 4A ). This
reaction decreased in ovariectomized group (II) (Figure 4B )
Figure 2. Mallory’s trichrome sections.
(A): Control group showing little collagen fibers (arrow) in between the lobules, around interlobular ducts and blood vessels. (B): Operated group showing increased collagen fibers (arrow)
in between the lobules, and around blood vessels.
(C): Treated group showing moderate amount of collagen fibers (arrows) in between the lobules. (Scale bar=25µm).
cytoplasm. The acini separated by thick connective tissue septa
Figure 3. Semithin sections stained with Toulidine blue.(A): Control group showing normal serous acini lined by pyramidal cells (C). They have basal vesicular nuclei (N) and apical secretory granules (G). Note, interlobular duct (D) in between the lobules have normal structure.
(B): Operated group showing irregular variable sized acini
(S).They have apoptotic nuclei (N) and vacuolated cytoplasm (V). Thick connective tissue septa are also seen (CT). The interlobular duct (D) has some darkely stained nuclei (n). (C): Treated group showing apparent normal serous acini (S) and interlobular ducts (D) of parotid gland. (Scale bar=5µm).

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Electron microscope results
Examination of the ultrathin sections of control group (I)
showed normal acinar cells with apical electron dense and
electron lucent secretory granules, densly packed rough en-
doplasmic reticulum and mitochondria ( Figure 5A ). Secretory
ducts lined mainly with cuboidal epithelium had rounded
nuclei and cytoplasmic granules. They attached together with
intercellular desmosomes ( Figure 5B ). While examination of
operated group (II) clarified the presence of apoptotic acinar
cells with irregular heterochromatic nuclei, dilated rarified
rough endoplasmic reticulum, electron lucent and electron
dense secretory granules. Other cells contained extensive
vacuoles in their cytoplasm ( Figure 5C ). The ducts of same
group contained apoptotic cells with irregular heterochro –
matic nuclei, many electron dense granules and intercellular
desmosomes ( Figure 5C ). On the other hand examination of
treated group (III) showed acinar cells with different affection;
some appeared apoptotic with heterochromatic nuclei, and
others appeared normal. Electron dense and electron lucent
granules, rough endoplasmic reticulum were seen in their
cytoplasm (Figure 5D ). Dilated duct with apparently normal
lining cells could be seen (Figure 5E ).
Morphometrical results
The duct diameter and the mean area % of collagen fiber for
all groups were presented in ( Table 1 and Figure 6 ): there was
a significant increase (P<0.05) in collagen % of OVX group (II)
compared with control group (I). While, there was a significant
decrease in collagen fiber % in treated group (group III) as
compared with OVX group (group II).
Figure 4. Immunohistochemical stained sections.
(A): control group showing moderate positive immunostaining reaction for Cu, Zn-SOD (arrow) in cytoplasm of acini.(B): Operated group showing mild positive
immunostaining reaction for Cu, Zn-SOD (arrow) in acinar
cell cytoplasm. (C): Section of treated group showing strong positive immunostaining reaction for Cu, Zn-SOD (arrow) in acinar cell cytoplasm. (Scale bar=20µm).
and became stronger in treated group (III) (Figure 4C ).Duct diameter Area %of collagen fiber Groups
33.3±10.62n11.4±2.24nControl(I)
65.07±9.78a20.51±4.6aOVX group(II)
40.44±9.2b14.46±3.79bTreated group (III)Table 1. Mean values of the area % of collagen fibers and the duct diameters in the different studied groups.
nnon-significant difference with group I
ahighly significant difference with group I
bhighly significant difference with the group II
Discussion
Several aspects of menopause are universal: hot flashes, exces –
sive transpiration, and vaginal atrophy, caused by estrogen
deficiency and manifested in most women after menopause.
The systemic aspects of menopause are well documented and
include oral manifestations, such as changes in salivary secre –
tion, gingivitis, bleeding, BMS and altered taste sensation [ 6].
Burning mouth syndrome (BMS) is a relatively common
condition with prevalence between 0.7 and 4.6% of the general
population. The etiology of this disorder is poorly understood
even though new evidence for a possible neuropathic patho –

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Figure 5. Ultrathin sections.
(A): Control group showing acinar cell with apical electron dense and electron lucent secretory granules (G), densely packed rough endoplasmic reticulum (Rr) and mitochondria(m). (B): Duct (D) is lined by rounded nuclei (n) and has cytoplasmic granules (g). Note, intercellular desmosome (arrowhead) inbtween the duct cells.
(C): Operated group showing irregular heterochromatic nucleus (N), dilated rarified rough endoplasmic reticulum (Rr),
electron dense secretory granules and electron lucent granules (G). Extensive cytoplasmic vacuolations (V) are seen in their cytoplasm.(D): Showing irregular heterochromatic nucleus (n) of lining epithelium of interlobular duct with many electron dense granules (g). Notice intercellular desmosomes (arrowhead). (E): Treated group showing some acini have heterochromatic nuclei (N), electron dense granules, electron lucent granules (G), and dilated rough endoplasmic reticulum (Rr). Other acinar cells have euchromatic nuclei (Nn).(F): Dialated duct (D) appears with apparently normal lining cells(C). (Scale bar=2µm).

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Figure 6. Histogram showing the area % of collagen fibers and
the duct diameters in the different studied groups.
genesis of idiopathic BMS is emerging [4].
Burning mouth syndrome may be primary (idiopathic)
[14,15] or secondary condition. Secondary type may be caused
by local or systemic disease, including nutritional deficiencies,
hormonal changes associated with menopause, local oral
infections, and denture-related lesions. Professional delay
in diagnosing, referring, and appropriately managing of BMS
patients occurs frequently. Treatment should be tailored to
each patient to avoid this condition [16-18].
Female sex steroids may have a beneficial effect on the
salivary glands [ 19] and some studies, Hietala [ 20] & Laine
[21] demonstrate increased saliva flow rate after hormone
treatment. During pregnancy, Hormone-related changes of
the composition could affect saliva function, increase the
severity of gingival inflammation [ 22] and lead to develop –
ment of gingival pyogenic granuloma [ 23].
The results of the present work provide evidence that ova –
riectomy induces different forms of degenerative changes in
parotid gland of group II. Most of the acini appeared irregular
with darkly stained nuclei and many vacuoles in their cyto –
plasm. They were separated by thickened septa containing
cellular infiltration. Homogenous acidophilic material was
also seen. The interalobular ducts were dilated and lined by
stratified epithelium. Congested blood vessels were also found.
These changes were reported by several studies younis
[24] & Stramandinoli-Zanicott et al., [ 25] who referred them
either to denervation of the gland or Hypocellularity, hypo –
vascularity and hypoxia.
Degenerated structures were replaced with homogenous
acidophilic areas which detected in gland. These amorphous
acidophilic areas were described as hyaline degeneration of
duct cells [ 26] Also, El-Sakhawy& Saeid [ 27] reported the same
histological changes in parotid gland. Estrogen regulates the
balance between endothelial dependent vasoconstrictor and
vasodilator influences, possibly via estrogen-specific actions
on nitric oxide and prostaglandin (PG2)-dependent pathways.
This leads to vasodiltataion of blood vessels and edema [ 28].
Edema manifested by cellular infilteration within thickened CT septa and blood vessels congestion [ 27].
Also, significant dilatation of the parotid ducts was evident
by morphometrical analysis of diameters of operated group.
Affection of the parotid ducts is related to accumulation of
ROS in their lining cells [ 29]. Collagen fibers appeared in
extensive amount in between the lobules and around blood
vessels in the same group. Estrogen is antioxidant hormone
and acts as radical scavengers and inhibits lipid peroxidation
in vivo and in vitro. So, low level of this hormone could lead
to oxidative stress in overiectomized rats [ 30]. RamosDeconte
et al., [ 31] reported that oxidative stress caused increase in
collagen fiber in parotid of diabetic rats.
In current work, operated group revealed mild positivity
for Cu, Zn-SOD while this immunoreaction became stronger
in treated group. These results in accordance with Kusunoki
et al [ 11]. They reported that administration of estrogen to
postmenopausal women will be useful for preventing senile
disturbances as osteoporosis, atherosclerosis, Alzheimer;s, etc.
Urabe [ 32], Mortel et al., [ 33] and Honjo [ 34] mentioned that
estrogen could suppress apoptosis in rat cranial nerve cells
[11]. Also some researchers Oztekin et al., [ 35] reported that
estradiol supplementation to ovariectomized rats decreased
lipid peroxidation in liver tissue.
Ultrastructurally, parotid gland of operated group (II)
clarified the presence of apoptotic acinar cells with irregular
heterochromatic nuclei, dilated rarified rough endoplasmic
reticulum, electron lucent and electron dense secretory
granules. Extensive cytoplasmic vacuoles and apoptotic cells
lining their ducts were also found. These results were in ac –
cordance with younis [ 24] and Omar [ 36] who concluded
that generation of large number of free radicals (nitrogen
&oxygen) could damage cellular proteins. Oxidative stress
caused by estrogen deficiency in this group is the major factor
that induced cellular damage. This damage might trigger the
process of apoptosis [ 30]. Steven and Lowe [ 37] concluded
that, the stagnant secretion in the excretory ducts might be
due to mitochondrial affections. This mitochondrial affec –
tion lead to depletion of ATP with failure of biosynthesis and
membrane pumps and as a result, the cells had no energy for
the process of secretion transport.
Moreover, researchers Tirapelli et al., [ 38] detected these
ultrastructural alterations in the parotid glands of alcoholic
animals. They explained the presence of cytoplasmic vesicles
by the great penetration of fluids in the cytoplasm of the
acinar cells. Dilatation of rough endoplasmic reticulum was
found in the acinar cells due to alterations in the cytoplasm
of the striated ducts [ 39].
In the current work, examination of treated group (III)
showed apparent normal appearance of serous acini and
ducts and moderate amount of collagen fibers. The acinar
cells appeared with different affection; some appeared ap –
optotic with heterochromatic nuclei, and others appeared
normal. Electron dense and electron lucent granules, rough
endoplasmic reticulum were seen in their cytoplasm. Dilated

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duct with apparently normal lining cells could be also seen.
To prove the role of a hormone in the pathogenesis of any
disease, firstly, hormone must first exist in the target tissue.
Second, the hormone’s specific receptor must reside in the
target tissue. Third, the absence of the hormone in the target
tissue should contribute to the onset of the disease. Finally,
the replacement of the hormone should induce the response.
It is known that sex steroids exist in saliva [ 40].
Ovaries are the main source of natural estrogens. Their
dysfunction decreases oestradiol level in blood and at the
same time its stimulatory function in target tissues. Presence
of estrogen receptors in cells of soft tissues causes changes
evoked by lack of natural estrogen [ 41,42]. Drugs used in the
prevention of postmenopausal osteoporosis and protect body
against alterations caused by hypoestrogenism. Prevention
of postmenopausal hypoestrogeny can be based not only on
simple supplementation with missing hormone, but also drugs
modulating estrogen receptors can be used, e.g. raloxifene
[43,44]. Changes caused by estrogen deficiency are manifested
in the vascular, urogenital and skeletal systems. There are
many studies about structural and functional changes in the
urogenital system in women.
Postmenopausal women frequently use hormonal therapy
which elevate estrogen in serum and affect the saliva com –
position of protein and carbohydrate structure [ 1]. It was
mentioned that a tissue-specific estrogen receptor is widely
expressed in both oral epithelium and the salivary glands.
Consequently, sex steroid hormone (estrogen) appears to play
an important and complex role in the regulation of salivary
glands especially ductal cells [ 7].
It was reported that low estrogen after ovariectomy reflects
trophical changes in many organs including salivary glands.
Oral discomfort in postmenopausal women may be improved
with replacement therapy. Also, this therapy leads to appar –
ent normalizing of oral salivary gland structure. Rahnama et
al., [ 3] and Kusunoki et al., [ 11] suggested that sex hormone
could influence age related histological changes in the pa-
rotid gland induced by apoptosis. Recently, administration of
estrogen to postmenopausal women reported to be useful
for preventing multiple senile disturbances.
The previous results concluded that estrogen deficiency
in postmenopausal women lead to variable degenerative
changes in parotid salivary glands of adult female albino
rats with relative limitation of these changes in estrogen
supplemented group. This may constitute an argument for
further more complex studies on biological and health con-
sequences of ovariectomized women, to test the necessity to
use hormonal replacement during menopause with special
recommendation to use estrogen as a protective measure.
Competing interests
The authors declare that they have no competing interests.Authors’ contributions DAM HME RAW
Research concept and design ✓ ✓ ✓
Collection and/or assembly of data ✓ ✓ –
Data analysis and interpretation ✓ – –
Writing the article ✓ – –
Critical revision of the article – ✓ ✓
Final approval of article – ✓ ✓Authors’ contributions
Acknowledgement
We would like to thank Dr. Mona El shwadfi for her aid
in statistical results.
Publication history
Editor: Paola Castrogiovanni, University of Catania, Italy.
Received: 29-Oct-2015 Final Revised: 30-Nov-2015
Accepted: 10-Dec-2015 Published: 22-Dec-2015
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Citation:
Mohamed DA, Elnegris HM and Wahdan RA. Histological effect of ovariectomy and estrogen replacement on parotid gland of adult albino rat.
J Histol Histopathol . 2015; 2:23.
http://dx.doi.org/10.7243/2055-091X-2-23