Lapatinib Decreases the Preimplantation Aneuploidy Rate of in vitro Fertilized Mouse Embryos without Affecting Completion of Preimplantation Development

2020 ◽  
pp. 1-8
Author(s):  
Parvaneh Maleki ◽  
Hamid Gourabi ◽  
Mohammad Tahmaseb ◽  
Afsaneh Golkar-Narenji ◽  
Masood Bazrgar

One of the major reasons for implantation failure and spontaneous abortion is a high incidence of preimplantation chromosomal aneuploidy. Lapatinib simultaneously inhibits EGFR and HER2, leading to apoptosis. We hypothesized a higher sensitivity for aneuploid cells in preimplantation embryos to lapatinib based on reports of aneuploid cell lines being sensitive to some anticancer drugs. Late 2-cell mouse embryos were treated with lapatinib after determining a nontoxic dose. Morphologies were recorded 24, 48, and 60 hours later. The effect of lapatinib on the aneuploidy rate was evaluated by studying blastocyst cells using FISH. Although the rate of development to 8-cell and morula stage was higher in the control group (<i>p</i> &#x3c; 0.05), there was no difference in development to the blastocyst stage at the same studied intervals between lapatinib-treated and control groups (<i>p</i> = 0.924). The mean number of cells in morula and blastocyst stages were not different between the groups (<i>p</i> = 0.331 and <i>p</i> = 0.175, respectively). The frequency of aneuploid cells and diploid embryos was, respectively, significantly lower and higher in lapatinib-treated embryos, (<i>p</i> &#x3c; 0.001). Since lapatinib treatment reduced the aneuploidy rate without impact on the development of mouse preimplantation embryos to the blastocyst stage and number of total cells, lapatinib seems useful for prevention of preimplantation aneuploidy in in vitro fertilization.

2005 ◽  
Vol 17 (2) ◽  
pp. 219 ◽  
Author(s):  
C.E. Ferguson ◽  
T.R. Davidson ◽  
M.R.B. Mello ◽  
A.S. Lima ◽  
D.J. Kesler ◽  
...  

There has been much debate over a direct role for progesterone (P4) in early bovine embryo development. While previous attempts to supplement bovine embryos in vitro with P4 produced results that vary and are often contradictory, this may be a response of administering P4 at inappropriate times. Therefore, the objective of these experiments was to determine if P4 could exert a direct effect on developing IVF-derived bovine embryos when administered at an appropriate time of embryo development. In Exp. I, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 168); (2) vehicle, CR1aa + ETOH (0.01%) (n = 170); and (3) P4, CR1aa + ETOH + P4 (20 ng/mL in 50-μL droplet) (n = 173). In Exp. II, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 160); (2) vehicle, CR1aa + DMSO (0.01%) (n = 180); and (3) P4, CR1aa + DMSO (0.01%) + P4 (20 ng/mL in 50-μL droplet) (n = 170). All embryos were evaluated on Days 6 to 9 post-insemination and rates calculated from 8-cell embryos. In Exp. I, ETOH tended to have a detrimental effect with significantly fewer (P < 0.05) embryos (53%) developing to the blastocyst stage on Day 7 compared with the control (62%) and P4 (71%) groups. At Day 7, significantly more embryos cultured in P4 (71%) developed to the blastocyst stage compared with the control group (62%). P4 treatment significantly increased the number of Grade 1 blastocysts (25%) on Day 7 compared with vehicle (15%) and control (17%) groups. At the end of culture, there were also significantly more Day 9 hatched blastocysts in the P4 group (33%) compared with vehicle (22%) and control (21%) groups. Supplementing P4 in the culture medium increased the rate of development, resulting in significantly more blastocysts (8%) on Day 6 and hatched blastocysts (21%) on Day 8 compared with vehicle (3% and 12%) and control (0% and 8%) groups, respectively. In Exp. II, there were no significant differences between treatment groups for Day 7 blastocysts (control 54%, DMSO 61%, P4 57%) and Day 9 hatched blastocysts (control 46%, DMSO 51%, P4 46%). However, there were significantly more Grade 1 blastocysts in the P4 group (22% and 36%) on Days 6 and 8 compared with vehicle (11% and 23%) and control (13% and 23%) groups, respectively. The lack of improvement in Day 7 blastocysts and Day 9 hatched blastocysts rates leads to further uncertainty in understanding the P4 vehicle interactions. In conclusion, the results of these two experiments indicate that P4 can exert a direct effect on the developing IVF-derived bovine embryo; however, due to P4 vehicle interactions; other inert vehicles need to be explored to further evaluate the direct effects of P4 on the developing bovine embryo.


2019 ◽  
Author(s):  
Mahboobeh Rasoulzadeh Bidgoli ◽  
robab latifnejad roudsari ◽  
ali montazeri

Abstract Background: Infertility is an emotional tension which influences the whole aspects of relationships in infertile couples. A main objective of infertility treatments is elevation of pregnancy rate. The present study aimed to examine the effect of collaborative counseling on pregnancy rate in infertile women, undergoing in vitro fertilization in Mashhad, Iran. Methods: In this clinical trial, 60 women with primary infertility were selected from an infertility research center and were randomly allocated into intervention (n=29) and control (n=31) groups. The intervention group received individual counseling, based on the collaborative reproductive healthcare model with collaboration of a midwife, a gynecologist and a clinical psychologist in five sessions during a two-month period. The control group received routine care. Positive pregnancy test was considered as a criterion of treatment success at the end of the study. Data were analyzed using statistical tests including independent samples t-test. Results: There was no significant difference in pregnancy rate between intervention and control groups (P = 0.298). Also, there were no significant differences in follicle and embryo numbers between two groups. However, a significant difference was observed between two groups in terms of oocyte numbers where the intervention group had more oocyte (P = 0.014). Conclusion: Overall the findings indicated that the collaborative infertility counseling did not improve treatment success in infertile women undergoing in vitro fertilization


2006 ◽  
Vol 18 (2) ◽  
pp. 250
Author(s):  
M. G. Marques ◽  
A. B. Nascimento ◽  
V. P. Oliveira ◽  
A. R. S. Coutinho ◽  
M. E. O. A. Assumpção ◽  
...  

The present work evaluated the reversible meiosis inhibition effect on the development of swine embryos produced by in vitro fertilization (IVF) or parthenogenetic activation (PA). The efficiency of PZM3 and NCSU23 embryo culture media was also evaluated. Oocytes from ovaries collected at a slaughterhouse were subjected to IVM in two different groups: CHX (cycloheximide 5 µM for 10 h) and control, both with TCM-199 + 3.05 mM glucose + 0.91 mM sodium pyruvate + 10% porcine follicular fluid (pFF) + 0.57 mM cystein + 10 ng epidermal growth factor (EGF)/mL + 10 IU eCG/mL + 10 IU hCG/mL for the initial 22 h. In the remaining period (20 h for CHX and 22 h for control), medium without hormones was utilized. After IVM, oocytes were denuded and fertilized for 6 h (IFV) or the matured oocytes were submitted to activation by electric pulses (PA) (2 DC of 1.5 kV/cm for 30 µs), incubated for 1 h in culture medium with 10 μM of CHX, and again submitted to the same electric pulses for 60 µs. Embryo development was evaluated by cleavage rate on Day 3 and blastocyst rate and blastocyst cell number on Day 7 of culture. Cleavage and blastocyst rates were analyzed by the equality-of-two-ratios test and cell number by the Kruskal-Wallis and Mann-Whitney tests (P < 0.05). In relation to IVF, the PZM3 medium was more efficient than NCSU23 for cleavage rate in the CHX group (PZM3: 68.4%, NCSU23: 44.4%) and had a better blastocyst rate in the control group (PZM3: 13.4%, NCSU23: 5.6%). With reference to PA, NCSU23 presented better cleavage and blastocyst rates than PZM3 in the CHX group (NCSU23: 89.5%, PZM3: 78.5% and NCSU23: 20.4%, PZM3: 13.0%, respectively). In the control group, only the NCSU23 blastocyst rate was higher than that for PZM3 (NCSU23: 22.5%, PZM3: 10.8%). No culture medium effect on cell number mean of IVF and PA blastocysts was observed. Maturation block improved cleavage rates in IVF groups cultured with PZM3 (68.4% and 50.6%, respectively, for CHX and control) and in PA groups cultured with NCSU23 (89.5% and 80.3%, respectively, for CHX and control), but no improvement of blastocyst rates in both groups (IVF and PA) was verified. Table 1 below shows that maturation block decreased the IVF and increased the PA blastocyst cell numbers. As older oocytes are more effectively activated, oocytes blocked with CHX achieved the maturation stage faster than the control group, therefore resulting in high-quality PA blastocysts. In conclusion, PZM3 was more efficient for IVF embryo production in contrast to NCSU23, whereas NCSU23 can be indicated for PA embryo production. Moreover, maturation blockage with CHX influenced blastocyst cell number, decreasing in IVF embryos and increasing in PA embryos. Table 1. Mean (±SD) of blastocyst cell numbers for IVF or PA groups after in vitro maturation without (control) or with cycloheximide (CHX) and cultured in NCSU23 or PZM3 medium This work was supported by FAPESP 02/10747–1.


2008 ◽  
Vol 20 (1) ◽  
pp. 118
Author(s):  
B. Gajda ◽  
Z. Smorag ◽  
M. Bryla

It is possible to improve the success of cryopreservation of in vitro-produced bovine embryos by modifying the embryos with the metabolic regulator phenazine ethosulfate (PES) (Seidel 2006 Theriogenology 65, 228–235). The PES treatment increased glucose matabolism, tended to increase the pentose phosphate pathway flux of glucose, and clearly reduced accumulation of lipids in cultured bovine embryos (De La Torre-Sanchez et al. 2006 Reprod. Fertil. Dev. 18, 597–607). It is known that porcine embryos have a considerably high content of lipids, and the success rates of their cryopreservation appear to be highly correlated with cytoplasmic lipid content. In our preliminary study, we observed that supplementation of NCSU-23 medium with PES has a positive effect on efficiency of pig blastocysts of good quality (Gajda et al.. 2007 Acta Biochim. Pol. 54(Suppl 1), 52 abst). In the present study, the effects of PES on pig blastocyst development, apoptosis, and survival after vitrification were investigated. In Exp. 1, porcine zygotes obtained from superovulated gilts were cultured in NCSU-23 medium supplemented with 0 (control), 0.025, 0.05, or 0.075 µm PES. The culture was performed at 39�C, with 5% CO2 in air, for 96–120 h. Embryo quality criteria were developmental competence (cleavage, morula stage, and blastocyst stage), cell number per blastocyst, and the degree of apoptosis as assessed by TUNEL staining. In Exp. 2, expanded blastocysts cultured with 0.025 µm PES were vitrified in a ethylene glycol and dimethyl sulfoxide mixture using open pulled straw (OPS) technology (Vajta et al. 1997 Acta Vet. Scand. 38, 349–352). After thawing, the blastocysts were cultured in vitro for re-expansion or transferred to synchronized recipients. Data were analyzed by chi-square test. There was a difference between the 0.025 µm PES-treated and the control group in percentage of cleaved embryos (99.0 and 91.4%, respectively; P < 0.05), between all experimental groups and control in percentage of morula stage (90.7, 87.8, 83.8, and 80.0%, respectively), and between 0.025 and 0.05 µm PES-treated and control in percentage of blastocyst rates (70.0, 75.5, and 65.7%, respectively). The number of cells and percentage of TUNEL-positive nuclei per blastocyst were lower in the PES-treated than in the control group. The survival rate of blastocysts after vitrification and thawing was enhanced in the presence of PES compared to that in the PES-free group (45.2 and 38.9%, respectively; P < 0.05). After transfer of 56 expanded blastocysts cultured with PES and vitrified into 3 recipients, two gilts were confirmed pregnant at 35 days of gestation. In conclusion, a higher blastocyst percentage with a low incidence of apoptosis was obtained in the presence of PES compared to control. These blastocysts also had an increased ability to survive cryopreservation.


2018 ◽  
Vol 30 (1) ◽  
pp. 189
Author(s):  
L. Landeo ◽  
R. S. Molina ◽  
M. E. Zuñiga ◽  
T. R. Gastelu ◽  
C. Sotacuro ◽  
...  

The objective of this study was to evaluate the in vitro developmental competence of alpaca embryos bisected at different embryonic stages. Gametes were obtained from ovaries and testes collected from a local abattoir. Cumulus-oocyte complexes (COC) were recovered (n = 120) by aspiration of ovarian follicles using a 5-mL syringe with an 18-gauge needle. Then, COC with at least 3 layers of cumulus cells and a homogeneous cytoplasm were matured in TCM-199 supplemented with 10% FCS, FSH (0.02 IU [JM1] [P2] [P3]), and 0.01 mg mL−1 oestradiol 17β [JM4] for 26 h at 38.5°C and 5% CO2 in air. After in vitro maturation, COC were placed in a 30-mL Petri dish containing FERT-TALP solution for 30 min. Then, epididymal alpaca spermatozoa (3 × 106 mL−1) were added to the dish and co-incubated with the COC for 20 h at 38.5°C and 5% CO2 in air. Motile epididymal sperm were selected by swim-up method centrifuged for 15 min at 350 × g in 2 mL of SPERM-TALP supplemented with 6 mg mL−1 of fatty-acid-free BSA. Sperm pellet was extended and culture in 5% CO2 in air at 38.5°C for 45 min. Thirty-three viable embryos at different stages [2-cells (n = 6), 8-cells (n = 15), and morulae (n = 12)] were bisected into approximately equal halves using a micro-surgical blade. The embryos were previously treated with 2 mg mL−1 of protease from Streptomyces griseus (P 8811, Sigma, St. Louis, MO, USA) for 2 min to remove the zona pellucida. After bisection, the demi-embryos were cultivated in in vitro culture (IVC) medium containing 0.036 mg mL−1 sodium pyruvate, 0.146 mg mL−1 l-glutamine, 1% essential amino acids, 0.5% nonessential amino acids, and supplemented with 10% FCS using the well-of-the-well system. The demi-embryos were incubated for 7 days (changing the media every 48 h) in 5% CO2 in air at 38.5°C. Additional embryos (n = 60) were obtained using the same conditions described above and used as a control group (unmanipulated). We obtained 66 demi-embryos [2-cells (n = 12), 8-cells (n = 30), and morulae (n = 24)] after bisection that were considered for IVC. From 12 demi-embryos bisected at 2-cell and 30 bisected at 8-cell stages, 3 (25%) and 30 (100%) reached the morula stage respectively. However, they did not develop any further. Interestingly, 18 demi-embryos bisected in morula reached the blastocyst stage (80%). For unmanipulated embryos, we obtained 42% (25/60), 35% (21/60), 32% (19/60), and 28% (17/60) of cleavage, morulae, and blastocyst and hatched blastocyst rates, respectively. In conclusion, alpaca embryos bisected at earlier stages (less than 8-cell) are not suitable to produce blastocysts. The earliest stage to produce blastocyst from bisected alpaca embryos is the morula stage.


2007 ◽  
Vol 19 (1) ◽  
pp. 185
Author(s):  
Y. Takagi ◽  
M. Shimizu ◽  
M. Morimura ◽  
S. Yokomizo ◽  
K. Hara ◽  
...  

Embryos of various species are successfully vitrified and cryopreserved in liquid nitrogen (&lt;−150°C). Like the preservation of frozen somatic cells cooled by dry ice (−79°C), the cryopreservation of embryos at −79°C is useful for a reduction in the shipping costs. The purpose of this study was to evaluate the effect of the cryopreservation period at −79°C on the in vitro embryo viability of vitrified mouse morulae after thawing. Morula-stage mouse embryos were collected from superovulated ICR donors 70 h after hCG injection. The embryos were exposed first to 5% DMSO + 5% ethylene glycol (EG) in Dulbecco's PBS + 20% FCS (mPBS) for 2 min, and then equilibrated for 20–30 s in a vitrification solution composed of 10% DMSO + 10% EG + 0.6 M sucrose in mPBS. The embryos were loaded onto cryoloops (Lane et al. 1999 Nat. Biotech. 17, 1234–1236) and plunged directly into liquid nitrogen. The cryoloops were placed in 1.2-mL cryotubes and stored in a −79°C freezer for 1–7 days. The embryos were warmed by passing through 4 dilution media and rinsed with mWM culture medium. They were then cultured at 37°C in 5% CO2 for 44 h. Non-cryopreserved embryos and embryos cryopreserved in liquid nitrogen served as controls. Data were analyzed by the chi-square test and the Student's t-test. Results are shown in Table 1. There was no significant difference (P &gt; 0.01) in the developmental abilities to the blastocyst stage of the vitrified embryos that were cryopreserved at −79°C for 1 day, 3 days, and 5 days, the embryos cryopreserved in liquid nitrogen, and the non-vitrified control. The blastocyst rate of embryos was significantly lower (P &lt; 0.01) for the Day 7 group than for the control group. The cell numbers of blastocysts were significantly lower (P &lt; 0.01) for the Day 1, Day 3, Day 5, and Day 7 groups than for the control group. This study suggests that vitrified mouse morulae can be successfully cryopreserved at −79°C for 5 days. Table 1. Effect of the cryopreservation period on the viability of vitrified mouse morulae preserved at −79°C


2008 ◽  
Vol 20 (1) ◽  
pp. 176
Author(s):  
D. X. Zhang ◽  
X. H. Shen ◽  
X. S. Cui ◽  
N.-H. Kim

MicroRNAs (miRNAs) are small (~22 nucleotides) non-coding RNA molecules that can regulate gene expression by base-pairing with fully or partially sequence-complementary target mRNAs. Hundreds of miRNAs have been identified in various multicellular organisms and many miRNAs are evolutionarily conserved. While miRNAs play an important role in animal development, little is known about their biological function during early mammalian development. In order to obtain insight into the role of miRNAs in early embryogenesis, we first determined the expression levels of three apoptosis-related miRNAs, miR-15a, -16, and -21 in mouse preimplantation embryos using TaqMan� MicroRNA Assays. Five embryos of each developmental stage were snap-frozen and amplified by stem-loop RT primer and TaqMan Universal PCR Master Mix (Applied Biosystems Inc., Foster City, CA, USA). The miRNA concentrations (10–X) in embryo samples were calculated by standard curve from synthetic lin-4 miRNA and the absolute copy number per embryo was obtained based on the formula of 6.02 � 10(8–X). All three miRNAs had low expression levels from the zygote to the 8-cell stage and were up-regulated thereafter. In general, among the three miRNAs, miR-15a exhibited the lowest expression in preimplantation embryos, while miR-16 exhibited the highest. Because of the low levels of miRNA-15a, we determined developmental ability and apoptosis of embryos following microinjection of miRNA-15a. The microinjection of miR-15a into zygotes did not affect embryo development up to the blastocyst stage (miR-15a, 90 � 4.5% v. buffer 94.6 � 5.8%); however, it did induce a significant degree of apoptosis (P < 0.05; Tukey's multiple range test). Furthermore, the expression levels of miR-15a and -16 were increased in microinjected blastocysts compared to the control group (copy number per blastocyst, miR-15a, 6991 � 1223 v. 3098 � 592; miR-16, 196216 � 958 v. 133514 � 6059). Real-time RT-PCR data showed that the gene expression levels of the housekeeping gene GAPDH, the anti-apoptotic gene Bcl-xL, and the miRNA pathway-related genes GW182 and Dicer remained unchanged in miR-15a-injected blastocysts compared to the control group. In contrast, the expression of the stem cell-specific transcriptional factor Oct-4 (fold change, 1.451 � 0.12), the pro-apoptotic gene Bax (1.418 � 0.12), and Caspase 3 (1.314 � 0.19) were significantly increased in microinjected blastocysts. In addition, treatment of 2-cell embryos with 600 µm H2O2 induced apoptosis and increased the expression level of miR-16 at the blastocyst stage (P < 0.05). Taken together, the changes in the expression levels of miR-15a, -16, and -21 in various embryonic developmental stages indicate a possible role for them in early embryogenesis. Furthermore, the high expression levels of miR-15a and miR-16 seem to be linked to apoptosis in blastocyst-stage embryos; this may be due to an increase in the expression of pro-apoptotic genes.


2021 ◽  
Vol 28 ◽  
pp. 112-116
Author(s):  
P. A. Trotskyi ◽  
O. V. Shcherbak ◽  
S. I. Kovtun

Aim. To evaluate the effectiveness of the use of nanomaterial in the environment for the further development of in vitro embryos derived from frozen-thawed oocytes in the system of conservation of genetic resources of animals at the cellular level. Methods. Biotechnological, cryobiological, morphological, cytogenetic, and statistical methods, as well as methods of statistical data processing were used in the research. Results. Oocyte-cumulus complexes (OCC) of cows were divided into four groups: three experimental, in which the maturation was performed in a medium containing 0.1, 0.01 and 0.001% UFS/sucrose and control - without the addition of nanobiomaterial. In vitro fertilization of pre-mature frozen-thawed ova of cows and subsequent maturation of embryos in the medium with the addition of UFS/sucrose (0.001%) showed an increase in the number of embryos by 16.7-22.1% compared with the addition of 0.1; 0.01% and 13.1% compared to the control group. It was found that the fragmentation rate of 2-cell cattle embryos decreased from 65.0 to 39.8% with a decrease in the concentration of UFS/sucrose from 0.1 to 0.001%. The most stable indicators of the fragmentation index from 78.4 to 50.0% were observed on the fourth day of embryo cultivation in experimental group B. Conclusions. Reducing the concentration of UFS/sucrose from 0.1 to 0.001% in the composition of the medium for in vitro maturation of cattle embryos leads to an increase of 16.7-22.1% in the number of embryos obtained. Keywords: oocyte-cumulus complex, cryopreservation, nanomaterial, in vitro maturation, embryo.


Author(s):  
Enis Ozkaya ◽  
Ebru Cogendez ◽  
Elif Tozkir ◽  
Saadet Unsal ◽  
Ahmet Yavuz ◽  
...  

OBJECTIVE: This study aimed to compare cycle outcomes among women with endometrioma or non-functional cysts versus control. STUDY DESIGN: Women under 35 years of age with unexplained infertility underwent in vitro fertilization cycle. Two hundred and ninety-nine women were included in this study. Study groups consist of women with endometrioma (n=82) or non-functional ovarian cysts (n=100) and control group (n=117). Women in each group were selected consecutively. Groups were matched for age and ovarian reserve and compared in terms of in vitro fertilization cycle outcome. RESULTS: There were no significant differences among groups in terms of mean age, early follicular phase Follicle-Stimulating Hormone, and anti-müllerian hormone levels (p>0.05). Baseline total antral follicle counts were similar among groups (p>0.05). There were significant differences among groups in terms of mean starting and total gonadotropin dose, peak estradiol level, total oocyte number, and mature oocyte numbers (p<0.05). Clinical pregnancy rates were 10.7%, 17.3%, and 31.6% in groups with non-functional cyst, endometrioma and control group respectively (p<0.05). The presence of a non-functional cystic mass of ovary on the starting day of stimulation was a risk factor for poor cycle outcome in terms of clinical pregnancy rates [OR=0.5 (95 % CI; 0.2-0.9, p=0.03)]. CONCLUSION: Our data showed that the presence of any kind of cystic mass of the ovary especially the non-functional cysts on the starting day of stimulation was a risk factor for poor cycle outcomes in terms of clinical pregnancy rates.


2009 ◽  
Vol 21 (1) ◽  
pp. 190
Author(s):  
T.-Y. Fu ◽  
P.-C. Tang

The endogenous non-coding microRNAs (miRNAs) of 18–25 nucleotides (nt) have been shown to involve in a wide variety of cellular processes as the posttranscriptional regulators by repression of translation or cleavage of mRNAs. In mammals, there are approximately 250 miRNAs that have been identified, and the cluster of miRNA-290 s (miR-290 s) has been demonstrated to express dramatically from the 2-cell to the 4-cell stage in mouse embryos examined from oocytes to the 8-cell stage. The association of miR-290 to 295 with pluripotency has been reported according to their specific expression in embryonic stem (ES) cells. It is interesting to explore the roles of these ES cell-specific miRNAs during the preimplantation stages and early differentiation at the blastocyst stage. Therefore, the objective of this study was to profile the expression pattern of ES cell-specific miRNAs (miR-291-5p, miR-293-3p, and miR-294-3p) from the 4-cell, 8- to 16-cell, morula, and blastocyst stages of mouse embryos. CD-1 F1 embryos at various developmental stages were collected from superovulated and naturally mated CD-1 mice. Total miRNAs of each stage analyzed were collected from 3 embryos for every replicate. Real-time RT-PCR was performed by using the specific stem-loop primers and the embryo lysate as template, which was prepared by heating in 4 μL of PBS at 95°C. Additionally, the in situ expressions of miR-291-5p, miR-293-3p, and miR-294-3p in mouse preimplantation embryos were confirmed by LNA™ probes specific for individual miRNAs. The embryo was fixed with 4% paraformaldehyde for 2 h at room temperature, followed by 3 times wash in PBST (0.1% TritonX-100 in PBS). After hybridization with individual 5′-fluorescein-labeled LNA™ probe, the embryo was washed with 0.1 × SSC, 2 × SSC, and TN buffer (0.1 m Tris-HCl, pH 7.5, 0.15 m NaCl) subsequently. The in situ expressions of miRNAs were detected by immunocytochemical reaction. The results indicated that the expressions of miR-291-5p, miR-293-3p, and miR-294-3p were up-regulated from the 4-cell to the morula stage and then down-regulated afterwards. It was found that the signals of miR-293-5p in an expanded blastocyst were weaker than those at the early blastocyst stage. However, it showed that the intensity of expression at the morula stage was 2 to 4 folds higher compared to that at the 4-cell stage in each miRNA analyzed. Also, the result showed that the ES cell-specific miRNAs examined were expressed in all cells in a blastocyst, i.e. tropectoderm and inner cell mass. In conclusion, we have established the expression profile of ES cell-specific miRNAs during preimplantation stages in mouse embryos. The specific roles of these miRNAs would be further investigated in the short future.


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