INTRODUCTION
The
endometrium is the innermost layer of the uterus and the place where the embryo
attaches. The endometrium plays a role in preparing for the implantation
process which involves the interaction between competent endometrial and
blastocyst receptivity. Therefore, this organ is important as a determining
factor for the success of a pregnancy related to the blastocyst implantation
process. However, it is not uncommon for this endometrium to experience damage
either caused by an action trauma, infection, or hormonal, causing disruption
of anatomical and physiological structures that adversely affect endometrial
receptivity.
Globally,
the prevalence rate of female infertility increased by 14.962% from 1366.85 per
100,000 in 1990 to 1571.35 per 100,000 in 2017 (Sun et al., 2019). Naturally, the probability of fertilization per cycle is relatively
low at around 30%, with two-thirds of infertility occurring due to implantation
failure. Assisted Reproductive Technology (ART) or assisted reproductive
technology is one of the treatments for infertility patients used to achieve
pregnancy in infertile couples who cannot be addressed the cause of infertility
conventionally. Assisted reproductive technology consists of various
techniques, one of which is in vivo fertilization (FIV) (Kim & Kim, 2017).
In
the past decade, the success of FIV has been low, especially in terms of
implantation rate (IR). Endometrial receptivity is highly correlated with IR,
in addition to embryonic quality. The average IR of the FIV program at 36 IVF
service centers in Indonesia is 19.3%. Low IR is
clinical evidence of impaired endometrial receptivity thought to be associated
with failure of the apposition, adhesion and invasion stages in the early
implantation and placentation processes. About 3% of FIV program cycles are
postponed due to non-optimal endometrial conditions, which are feared to interfere
with embryo implantation (Nazari et al., 2019).
The
FIV method includes highly coordinated steps, starting with controlled ovarian
stimulation with exogenous gonadotropins, oocyte and sperm collection,
fertilization, then embryo transfer into the uterus. In the FIV program,
ovarian stimulation was carried out with two types of protocols, namely
antagonist and agonist. Antagonistic protocols are preferred by clinicians
because they are cheaper, easier to perform, and require a shorter time, making
them more comfortable for patients than agonist protocols. Meanwhile,
stimulation of the ovaries with both types of protocols will disrupt the
physiological endocrine milieu which will result in disruption of the
regulation of estrogen and progesterone receptors in
stroma and endometrial epithelial cells.
Supphysiological levels of the hormones estrogen and progesterone in the early luteal phase are
thought to indirectly affect the expression of cell adhesion molecules,
especially homeobox A 10 (HOXA10) in endometrial epithelial cells. This can
reduce endometrial receptivity, resulting in lower implantation rates.
Endometrial
receptivity is an important predictor of pregnancy after FIV and embryo
transfer. Endometrial thickness is used as an indicator for endometrial receptivity.
Endometrial thickness was measured on the day of administration of the hormone
chorionic gonadothrophin (hCG)
and measured using transvaginal ultrasound in the mid-sagittal plane, where
this method is considered non-traumatic and simple. The effect of endometrial
thickness on FIV success has been evaluated by many investigators. A recent
meta-analysis study demonstrated that the probability of clinical pregnancy in
patients with an endometrial thickness of <7 mm was significantly lower than
in patients with an endometrial thickness of >7 mm (Wu et al., 2014).
Various
attempts have been made to improve receptivity in the endometrium, such as
antibiotic therapy, curettage and therapeutic biopsy of polyposis, myomectomy
and other appropriate therapies. In addition, corrective efforts have been made
to endometrial receptivity with prolongation of estrogen
administration, gonadotropin therapy, low-dose administration of hCG, aspirin, sildenafil, acupuncture and stem cell
therapy, but the results have not been satisfactory (Zadehmodarres et al., 2017); (Eftekhar et al., 2018).
At
the molecular level, endometrial damage is thought to be related to the role of
adhesion and inflammation molecules, one of which is homeobox A 10 (HOXA10)
which is a family of GATA transcription factors. HOXA10 is one of the genes
that is normally up regulated in the endometrium during the implantation window
period and its levels increase dramatically during the secretion phase midway
of the menstrual cycle. β3 integrins are adhesion molecules to the
endometrium that are locally responsible for the presence of pinopods, where β3 integrins are directly regulated by
HOXA10 (Lessey & Young, 2019).� HOXA10 is thought to work
optimally in the administration of autologous platelet rich plasma in damaged
endometrium.
Platelet
rich plasma (PRP) is an autologous blood product that carries platelet-rich
products three to five times the normal amount. The content of PRP consists of
growth factors, chemokines, cytokines, nutritional hormones, stabilizing
proteins, such as albumin and other products that can function for cell growth
and homeostasis (Zadehmodarres et al., 2017). PRP contains many α that play an important role in the storage of
intracellular growth factors, such as platelet-derived growth factor (PDGF),
transforming growth factor (TGF)-� and insulin-like growth factor (IGF)-1 (Dhurat & Sukesh, 2014).
PRP
is known to have proliferative and anti-fibrotic effects on damaged
endometrium, where PRP administration can also trigger angiogenesis and cell
migration associated with increased endometrial thickness. Thus, administration
of PRP can increase endometrial receptivity associated with increased IR. Thus,
the success of IR in FIV with pathological endometrial conditions or
PRP-exerted endometrial damage is thought to be related to the role of HOXA10 (Du & Taylor, 2016); (Lee et al., 2017).
Research
shows that the addition of PRP to endometrial preparation of FIV with Frozen
Embryo Transfer (FET) was found to significantly increase endometrial thickness
where endometrial thickness correlates with good endometrial receptivity, thus
increasing the IR number in the cycle. Research also proves that the
administration of PRP to the endometrium with a history of previous disruption
also experienced anatomical and histological improvements through a complex
process of growth hormone. However, the question is whether PRP administration
will also increase endometrial HOXA10 expression in the FIV antagonist
protocol.
Based
on the above background, research was conducted on the effect of autologous
platelet rich plasma (PRP) administration on ovarian stimulation in vitro
fertilization antagonist protocol on homeobox A 10 (HOXA10) endometrial expression
of wistar strain rats.
This
study aims to prove the effect of Autologous PRP administration on the FIV
antagonist protocol on endometrial receptivity. This study aims to prove that
administration of Autologous PRP on antagonist protocol causes homeobox A 10
(HOXA10) expression in the endometrium of wistar
strain rats is higher than without autologous PRP administration.
Through this study, it is hoped that benefits can be obtained regarding the latest understanding related to the administration of Autologous PRP on ovarian stimulation protocols with GnRH antagonists to the expression of homeobox A 10 (HOXA10) endometrium of wistar strain rats. High HOXA10 expression will be associated with increased endometrial receptivity and implantation rate in pregnancy success.
The
design of this study was experimental the randomized posttest only controlled
group design using experimental animals of female rats of the wistar strain.
The research design is described as follows:
Figure 1. Research design
Information:
P ���������� = Population
R ���������� = Randomization
S ���������� = Sample
Ra �������� = Random allocation
p (+)������ = PRP therapy group on ovarian stimulation with GnRH
antagonist protocol
p (-) ����� = Group without PRP administration on ovarian stimulation with
GnRH
antagonist protocol
O1 ������� = Observation of endometrial HOXA10 expression in the PRP
therapy group
O2������ = Observation of endometrial HOXA10 expression in the group
without PRP ad
Ministration
Observation, maintenance, physical examination,
vaginal swab examination, randomization of samples, and collection of rat
endometrial tissue were carried out at the Biomedical Laboratory of the Animal
Lab Unit, Faculty of Medicine, Udayana University,
Denpasar. Immunohistochemical examination is carried out at the Biomedical
Laboratory of the Faculty of Medicine, Udayana
University, Denpasar. The study was conducted in April � June 2022.
RESULTS AND DISCUSSION
Characteristics of the Research Subject
This research is an
experimental study with the randomized posttest only controlled group design.
The study was conducted on 40 wistar strain rats which were divided into 2
groups, namely 20 as the treatment group and 20 as the control group. Wistar
rats with a regular estrus cycle of 4 days, aged 8-12 weeks, with a body weight
of 200-230 grams were used as the target population of the study. This research
was conducted at the Integrated Biomedical Laboratory, Faculty of Medicine,
Udayana University, Denpasar.
This research has received
approval from the Integrated Biomedical Laboratory Unit, Faculty of Medicine,
Udayana University with a research implementation approval letter No: 1112/UN14.2.2.VII.6/LT/2022
and ethical feasibility approval from the Research Ethics Commission Unit,
Faculty of Medicine, Udayana University dated December 31, 2021, in the form of
Ethical Clearance Number: 2898/UN14.2.2.VII.14/LT/2021.
All data from treatment and
control groups that had met the inclusion and exclusion criteria in this study
were then tested for normality using the Kolmogorov-Smirnov test.
Descriptively, the characteristics of research subjects in the treatment and
control groups are presented in the following table.
Table 1. Characteristic Distribution of Treatment and
Control Groups
|
Average |
Treatment Group (N=20) |
Control Group (N=20) |
p-value* |
||
|
Rerata |
SD |
Rerata |
SD |
||
|
Age |
62,95 |
1,31 |
62,45 |
1,60 |
0,288 |
|
Initial Weight Loss |
211,24 |
1,73 |
211,85 |
1,61 |
0,257 |
|
Final Weight Loss |
227,69 |
1,36 |
228,30 |
1,26 |
0,152 |
*T-independent
test
Based on table 1. It can be
seen that the average age of Wistar strain rats during the study in the
treatment group was 62.95 � 1.31 days, while in the control group was 62.45 �
1.60 days. Body weight of wistar rats was measured before and after the study.
The average initial body weight of wistar strain rats in the treatment group
was 211.24 � 1.73 grams, while in the control group was 211.85 � 1.61 grams. At the end
of the study, there was an increase in body weight with the average body weight
of the treatment group wistar strain rats was 227.69
� 1.36 grams, while in the control group was 228.30 � 1.26 grams. The
Kolmogorov-Smirnov test obtained a significance value of more than 0.05 which
means that the data are normally distributed on age, early and late body weight
of wistar strain rats.
Furthermore, in the T-independent test, a significance value of more than
0.05 was obtained which stated that there was no significant difference in
average age, initial and late body weight between the treatment and control
group wistar strain rats. Other control variables
have been adjusted by conditioning wistar rats to the
same conditions, including cage size, temperature, humidity, type of food and
how to give it, adaptation to light and dark environments and the process of
health checks to rule out infections or abnormalities.
HOXA10 Expression in the Endometrium of Wistar Strain
Rats
To assess HOXA10 expression in the endometrium of wistar
strain rats was carried out by immunohistochemical examination and H-score
calculation. H-score is calculated by the following equation: H-Score = ΣPi (i + 1). Intensity (i) represents the core staining of HOXA10 indicated by a
value of 0, 1, 2, or 3 (negative, weak, medium or strong) and Pi is the
percentage of core staining for each intensity, ranging from 0-100% (Simpson & Kelly, 2011). The following are the results of H-Score
HOXA10 in the treatment and control groups (Figure 2).
Figure 2. HOXA10 H-Score Graph
Figure 2 shows the results of immunohistochemical examination in sample
treatment group no. 14 with a total of 343 epithelial cells with negative
staining of 11 epithelial cells, weak intensity 72 epithelial cells, moderate
intensity 103 epithelial cells and strong intensity 157 epithelial cells. The
H-score obtained is 3.18 which means the expression is very strong.
Figure 3. HOXA10 Expression in The Treatment Group
Figure 3 shows the results of
immunohistochemical examination in sample control group no. 21 with a total of
328 epithelial cells with negative staining of 193 epithelial cells, weak
intensity 87 epithelial cells, moderate intensity 32 epithelial cells and
strong intensity 4 epithelial cells. The H-score obtained is 1.52 which means
medium expression.
Figure 4. HOXA10 Expression In The Control Group
Effect of Autologous PRP Administration on HOXA10
Expression in the Endometrium of Wistar Strain Rats
In this study, the results of H-score HOXA10 were tested for data
normality using the Kolmogorov-Smirnov test, it was found that the H-score
HOXA10 data of the treatment and control groups were normally distributed, so
that to conduct a data comparison test used was a T-independent test.
Table 2. H-score HOXA10 normality test
|
Parameters |
p-value* |
|
H-score HOXA10 Treatment Group H-score HOXA10 Control Group |
0,200 0,200 |
*
Kolmogorov-Smirnov test
Based on immunohistochemical
examination of endometrial tissue of wistar strain rats, HOXA10 H-score results
were obtained in the treatment group, namely 2.86 to 3.52 with an average of
3.15 + 0.20. A lower HOXA10 H-score result was obtained in the control group,
which was 1.43 to 2.18 with an average of 1.68 + 0.20. In table 5.3 it has been
described that the T-independent test with p-value results of 0.000 < 0.05.
These results showed that the average H-score in the treatment group was
significantly higher than in the control group.
Table 3 H-score HOXA10 Expression in Endometrial of
Wistar Strain Rats
|
Average |
Treatment Group (N=20) |
Control Group (N=20) |
p-value* |
||
|
Average |
SD |
Average |
SD |
||
|
H-score HOXA10 |
3,15 |
0,14 |
1,68 |
0,20 |
0,000 |
*T-independent test
Furthermore, the HOXA10 H-score
was grouped into HOXA10 expression levels as follows: (a) weak expression
(H-score < 1.1), (b) medium expression (H-score = 1.1 � 2), (c) strong
expression (H-score = 2.1-3), and (d) very strong expression (H-score = 3.1 �
4). The Chi-square test was then used to compare HOXA10 expression between the
treatment group and the control group (Table 3).
In the treatment group, 20 rats
(100%) had strong and very strong HOXA10 expression and no mice had weak and
moderate HOXA10 expression. In contrast, in the control group, 18 mice (90%)
had weak and moderate HOXA10 expression and only 2 mice (10%) had strong and
very strong expression. With the Chi-Square Test it was found that the value of
2 = 32.7 and the p-value 0.000 <0.05. This indicates that there is a
significant difference in HOXA10 expression between the treatment and control
groups. Thus the initial hypothesis was proven, namely the administration of
PRP in the in vitro antagonist protocol increased the expression of HOXA10 in
the endometrium of Wistar rats.
Table 4 Differences in HOXA10 expression between
the treatment group and the control group
|
|
|
HOXA 10 Expression |
c2 |
p-value* |
||
|
|
Weak and moderate |
Strong and very powerful |
||||
|
Group |
|
Treatment |
0 (0%) |
20 (100%) |
32,7 |
0,000 |
|
Control |
18 (90%) |
2 (10%) |
||||
* Chi-square
Test
DISCUSSION
Characteristics of the Research Subject
In this study, the average age of wistar strain rats when the study began in the treatment
group was 62.95 days and the control group was 62.45 days. Research subjects
from both research groups have entered the period of reproductive maturity,
where the age of wistar strain rats more than 60 days
is classified into the adult stage (Jackson et al., 2017).
The body weight of the mice was affected by
age, sex and diet. In this study, the average body weight increase of wistar strain rats in the treatment group was 211.24 grams
to 227.69 grams and the control group by 211.85 grams to 228.30 grams. The
increase in body weight of study subjects from the beginning to the end of the
study reflected a good state of health. It is known that the body weight, age
and stage of development of experimental animals can affect the results of
studies (Kilkenny et al., 2009); (Ghasemi et al., 2021).
Effect of Platelet-Rich Plasma Administration on HOXA
10 Endometrial Expression of Wistar Strain Rats on Ovarian Stimulation In Vitro
Fertilization Antagonist Protocol
In this study, HOXA10 H-scores were obtained from 1.43 to 2.18 with a
mean of 1.68 + 0.20 in the endometrium of the control group of Wistar rats that
had received ovarian stimulation with GnRH antagonists. In the treatment group
with ovarian stimulation with GnRH antagonists followed by PRP administration,
the HOXA10 H-score was much higher, from 3.04 to 3.52 with a mean of 3.32 +
0.14 compared to the control group.
HOXA10 plays an important role in both endometrial implantation and
decidualization. HOXA10 expression has been widely observed in endometrial
stromal cells, endometrial glands and endometrial epithelial cells. Loss of
HOXA10 has no adverse impact on embryo survival during the embryo transfer
period, but profoundly affects function and implantation in the endometrium. In
humans, it is known that defects in the implantation process occur along with
lower HOXA10 expression. The important role of HOXA10 during implantation is
proven by transgenic mouse model experiments and decreased implantation rates
through changes in HOXA10 expression (Lee et al., 2017).
In women, HOXA10 expression
increases in the midluteal phase at implantation which plays a role in
endometrial receptivity (Du & Taylor, 2016). Strong immunoreactivity in HOXA10 was found in the endometrial stroma
of fertile women with an H-Score of 2.1 (Phillips et al., 2010). HOXA10 is a good biomarker for endometrial receptivity and changes in
its methylation have been shown to be associated with impaired endometrial
receptivity in several pathological endometrial conditions, including diseases
of the reproductive system and external factors that disrupt the endocrine
system (Li, et al., 2015).
Administration of GnRH antagonists in ovarian stimulation, can interfere
with the expression of HOXA10 in endometrial stromal cells, thereby affecting
endometrial receptivity. There was an
increase in oocyte production, but a relatively low implantation rate was found
so that most embryo implantation failures occurred. However, GnRH antagonists
have been shown to be effective, safe and the therapeutic benefits outweigh the
negatives, so they should continue to play a role in controlled ovarian
stimulation. The results of the study by Rackow, et
al. (2008) support the molecular basis for the lower pregnancy rates seen
clinically with the use of GnRH antagonists. Based on the results of this
study, it was found that in female endometrial stromal cells, the H-score
HOXA10 was significantly lower in the administration of GnRH antagonists of
1.50 � 0.18 compared to the administration of GnRH agonists of 2.51 � 0.12 and
the control group of normal cycles of 2.31 � 0.07. Other studies also obtained
the same results, namely HOXA10 protein expression was found to be lowest in
the rat endometrium of the treatment group with GnRH antagonists and highest in
the natural cycle control group followed by GnRH agonists.
Decreased expression of HOXA10
during the midluteal phase of the menstrual cycle is seen in other conditions
associated with implantation disorders, such as PCOS, submucosal uterine myoma,
hydrosalfing and endometriosis; (de Mola, 2014). The expression of HOXA10, LIF and integrin-β3 proteins is also
decreased in Ovarian Hyperstimulation Syndrome (OHSS). Studies have shown that
during the FIV cycle, the incidence of moderate OHSS is 3-6% and the incidence
of severe OHSS is 0.2-1%. Pregnancies associated with OHSS have been found to
have a higher incidence of complications, including gestational diabetes
mellitus, placental abruption, prematurity, stillbirth, low birth weight and
preterm birth (Xu & Tang, 2014).
Understanding the mechanism of HOXA10 expression is critical in finding
potential therapies to improve the condition of implantation disorders with
decreased HOXA10 expression. Research results Jang, (2017) demonstrated that
intrauterine administration of autologous PRP exerts proliferative and
antifibrotic effects on damaged endometrium. PRP is known to contain a number
of growth factors and cytokines that can help accelerate cell proliferation,
angiogenesis, cell migration, accelerate healing and tissue regeneration.
Analysis on the expression of Ki-67, CK, VEGF, and HOXA10 showed significant
semi-quantitative differences with PRP administration. HOXA10 was found to be
an important transcription factor for many target genes involved in regulating
endometrial function and development during the menstrual cycle, together with
endometrial receptivity to establish the necessary conditions for implantation
in humans and mice. In that study, the expression of HOXA10 upon PRP
administration increased significantly on IHC staining. Similar results were
also observed for HOXA10 mRNA expression by RT-PCR. These results provide
correlative evidence for the possible use of PRP in achieving implantation with
increased uterine vascularity and endometrial receptivity (Kushnir et al., 2017).
PRP contains several growth factors and
cytokines, including: platelet-derived growth factor (PDGF), fibroblast growth
factor (FGF), vascular endothelial growth factor (VEGF), epidermal growth
factor (EGF), insulin-like growth factors I, II (IGF I, II), fibroblast growth
factor (FGF), transforming growth factor (TGF), connective tissue growth factor
(CTGF) and interleukin 8 (IL-8) that promote stimulation, proliferation and
regeneration. It has been shown that intrauterine infusion of PRP can increase
endometrial thickness and pregnancy rates in the FIV cycle (Chang et al., 2019);(Zadehmodarres et al., 2017).
PRP significantly stimulated growth, migration
and adhesion of endometrial mesenchymal stem cells when compared to the control
group. Data showed that there was endometrial expansion and pregnancy with the
use of PRP infusion so that the pregnancy rate reached 60% (Wang et al., 2019). Other studies
have shown that PRP is effective in increasing pregnancy rates in recurrent
implantation failures. In the PRP group compared to the control group, the
results of a higher chemical pregnancy rate of 53.06% vs 27.08% and a higher clinical
pregnancy rate of 44.89% vs 16.66% (Nazari et al., 2019).
CONCLUSION
Based on the results of this study, it can be
concluded that PRP administration in ovarian stimulation antagonist protocol
showed significantly higher endometrial HOXA10 expression of wistar strain rats compared to without PRP administration.
In the administration of PRP, the results of HOXA10 expression were obtained
which were strong and very strong significantly.
BIBLIOGRAFI
Chang, Y., Li, J., Wei, L., Pang, J., Chen, J., &
Liang, X. (2019). Autologous platelet-rich plasma infusion improves clinical
pregnancy rate in frozen embryo transfer cycles for women with thin
endometrium. Medicine, 98(3).
de
Mola, J. R. L. (2014). Principles and practice of assisted reproductive
technology. Fertility and Sterility, 102(2), 610.
Dhurat,
R., & Sukesh, M. (2014). Principles and methods of preparation of
platelet-rich plasma: a review and author�s perspective. Journal of
Cutaneous and Aesthetic Surgery, 7(4), 189.
Du,
H., & Taylor, H. S. (2016). The role of Hox genes in female reproductive
tract development, adult function, and fertility. Cold Spring Harbor
Perspectives in Medicine, 6(1), a023002.
Eftekhar,
M., Neghab, N., Naghshineh, E., & Khani, P. (2018). Can autologous platelet
rich plasma expand endometrial thickness and improve pregnancy rate during
frozen-thawed embryo transfer cycle? A randomized clinical trial. Taiwanese
Journal of Obstetrics and Gynecology, 57(6), 810�813.
Ghasemi,
A., Jeddi, S., & Kashfi, K. (2021). The laboratory rat: Age and body weight
matter. EXCLI Journal, 20, 1431.
Jackson,
S. J., Andrews, N., Ball, D., Bellantuono, I., Gray, J., Hachoumi, L., Holmes,
A., Latcham, J., Petrie, A., & Potter, P. (2017). Does age matter? The
impact of rodent age on study outcomes. Laboratory Animals, 51(2),
160�169.
Kilkenny,
C., Parsons, N., Kadyszewski, E., Festing, M. F. W., Cuthill, I. C., Fry, D.,
Hutton, J., & Altman, D. G. (2009). Survey of the quality of experimental design,
statistical analysis and reporting of research using animals. PloS One, 4(11),
e7824.
Kim,
S. M., & Kim, J. S. (2017). A review of mechanisms of implantation. Dev
Reprod 21: 351�359.
Kushnir,
V. A., Barad, D. H., Albertini, D. F., Darmon, S. K., & Gleicher, N.
(2017). Systematic review of worldwide trends in assisted reproductive
technology 2004�2013. Reproductive Biology and Endocrinology, 15,
1�9.
Lee,
B. H., Yang, J.-H., Kim, H.-S., Suk, K.-S., Lee, H.-M., Park, J.-O., Moon,
S.-H., Cho, H. W., Suh, J.-S., & Park, J.-O. (2017). Effects of autologous
platelet-rich plasma on regeneration of damaged endometrium in female rats. Yonsei
Medical Journal, 58(6), 1195�1203.
Lessey,
B. A., & Young, S. L. (2019). Structure, function, and evaluation of the
female reproductive tract. In Yen and Jaffe�s Reproductive Endocrinology
(pp. 206�247). Elsevier.
Nazari,
L., Salehpour, S., Hoseini, S., Zadehmodarres, S., & Azargashb, E. (2019).
Effects of autologous platelet-rich plasma on endometrial expansion in patients
undergoing frozen-thawed embryo transfer: a double-blind RCT. International
Journal of Reproductive BioMedicine, 17(6), 443.
Phillips,
P. M., Jarema, K. A., Kurtz, D. M., & MacPhail, R. C. (2010). An
observational assessment method for aging laboratory rats. Journal of the
American Association for Laboratory Animal Science, 49(6), 792�799.
Simpson,
J., & Kelly, J. P. (2011). The impact of environmental enrichment in
laboratory rats�behavioural and neurochemical aspects. Behavioural Brain
Research, 222(1), 246�264.
Sun,
H., Gong, T.-T., Jiang, Y.-T., Zhang, S., Zhao, Y.-H., & Wu, Q.-J. (2019).
Global, regional, and national prevalence and disability-adjusted life-years
for infertility in 195 countries and territories, 1990�2017: results from a
global burden of disease study, 2017. Aging (Albany NY), 11(23),
10952.
Wang,
X., Liu, L., Mou, S., Zhao, H., Fang, J., Xiang, Y., Zhao, T., Sha, T., Ding,
J., & Hao, C. (2019). Investigation of platelet‐rich plasma in
increasing proliferation and migration of endometrial mesenchymal stem cells
and improving pregnancy outcome of patients with thin endometrium. Journal
of Cellular Biochemistry, 120(5), 7403�7411.
Wu,
Y., Gao, X., Lu, X., Xi, J., Jiang, S., Sun, Y., & Xi, X. (2014).
Endometrial thickness affects the outcome of in vitro fertilization and embryo
transfer in normal responders after GnRH antagonist administration. Reproductive
Biology and Endocrinology, 12, 1�5.
Xu,
C. K., & Tang, S. B. (2014). Alteration of endometrial receptivity in rats
with ovarian hyperstimulation syndrome. Journal of Obstetrics and
Gynaecology, 34(2), 146�152.
Zadehmodarres,
S., Salehpour, S., Saharkhiz, N., & Nazari, L. (2017). Treatment of thin
endometrium with autologous platelet-rich plasma: a pilot study. JBRA
Assisted Reproduction, 21(1), 54.
