Human embryology is the study of development from a single cell to a baby in 9 months. Implantation occurs at the end of the first week of development. The second week of development is known as the week of 2's. Gastrulation, the most characteristic event occurring in the third week, establishes three germ layers composed of ectoderm, mesoderm, and endoderm. The three germ layers and neural crest cells lead to the development of their own tissues and organs during the embryonic period, which extends from the third to the eighth week. Major congenital malformations occur in the embryonic period. The fetal period, from the third month to the day of birth, is the time for maturation of tissues and organs, and growth of the body. Because of the close relationship between embryology and congenital abnormalities, knowledge of human development is essential to assess the effects on the embryo when the mother has been exposed to teratogens. This paper briefly reviews the normal embryonic development and associated congenital malformation.
Congenital Abnormalities ; Ectoderm ; Embryology ; Embryonic Development* ; Embryonic Structures* ; Endoderm ; Female ; Gastrulation ; Germ Layers ; Human Development ; Humans* ; Mesoderm ; Mothers ; Neural Crest ; Neurulation ; Parturition ; Pregnancy ; Teratogens

OBJECTIVETo explore effects of acupuncture on embryo implantation and development in the rat with dysfunctional embryo implantation.

METHODSThe pregnant rats were randomly divided into a control group, a model group and an acupuncture group. In the model group and the acupuncture group, the dysfunctional embryo implantation were developed by Mifepristone, and the acupuncture group were treated with acupuncture for one consecutive week fro the first day of pregnancy. The pregnant rate, the average embryo implantation number, weight of the uterus, ovary and the size and weight of single embryo were compared among the 3 groups, and optical microscope was used for comparison of the morphological structures of the endometrium and ovary were compared among the 3 groups.

RESULTSIn the acupuncture group, the pregnant rate, the average embryo implantation number were more significantly increased as compared with the model group (P < 0.01); in the model group, the weight of the uterus and ovary were lighter than those in the control group and the acupuncture group, with poor development of the endometrium in the model group, but development of the endometrium in the acupuncture group was similar to that in the control group.

CONCLUSIONAcupuncture can reverse Mifepristone's anti-implantation effect to a certain extent, and promote implantation and development of embryo in the rat.

Acupuncture Therapy ; Animals ; Embryo Implantation ; drug effects ; Embryonic Development ; Female ; Mifepristone ; pharmacology ; Pregnancy ; Rats

OBJECTIVETo evaluate the impact of sperm midpiece morphology observed under high-power microscope on embryo development following intracytoplasmic morphologically selected sperm injection.

METHODSMorphologically normal sperms from 57 patients undergoing intracytoplasmic sperm injection (ICSI) for male-factor infertility were selected microscopically (magnification of ×200 or 400) and subjected to motile sperm organellar morphology examination (MSOME) at high magnification of ×6000. According to the morphology of sperm medpiece, the sperms were divided into 3 groups, namely group A with a/b of 1-1.2, group B with a/b≥1.5, and group C with irregular morphology. The sperms in the 3 groups were intracytoplasmically injected in oocytes and the outcomes of the embryos were compared.

RESULTSGroups A, B, and C showed significant differences in the rate of ET-D3 top quality embryo (79.7% vs 55.6 % vs 33.3%) and implantation rate (43.2% vs 11.1% vs 0%), but not in the fertilization rate (73.3% vs 80.4% vs 63.5%), blastocyst formation rate (23.2% vs 22.2% vs 9.09%), cryopreservation rate (29.2% vs 25.0 % vs 13.0%), or D3 top quality embryo rate (35.3% vs 37.8% vs 18.8%).

CONCLUSIONSIn ICSI cycle, selecting morphologically normal sperms for intracytoplasic injection can increase the normal fertilization rate and top quality embryo rate on the transfer day and improve the implantation rate of the embryo.

Cryopreservation ; Embryo Implantation ; Embryonic Development ; Female ; Fertilization ; Humans ; Infertility, Male ; Male ; Oocytes ; Semen Analysis ; Sperm Injections, Intracytoplasmic ; Sperm Midpiece ; physiology

OBJECTIVE: The purpose of the current series of experiments were to assess the effect of GM-CSF, as a medium supplement, on the development of mouse embryos and the expression of LIF and IL-1beta mRNA. MATERIALS AND METHODS: Mouse 2-cell embryos were collected from the oviducts of 6 weeks old ICR mice at 48 hours after hCG injection. Embryos were cultured in P-1 medium supplemented with mouse GM-CSF(0,1,5,10 ng/ml). The embryo development to blastocysts and hatching blastocysts was assessed and the cell number in blastocyst was also examined. Using RT-PCR, the expressions of LIF and IL-1beta mRNA in blastocyst were evaluated in the GM-CSF supplemented group and control group. RESULTS: In mouse, the addition of GM-CSF increased the percentage of blastocysts(65.5%, 68.6%, 73.0% and 76.1% for control and 1, 5 and 10 ng/ml, respectively), and increased the proportion of hatching blastocysts(35.2%, 36.4%, 43.2% and 53.0% for control and 1, 5 and 10 ng/ml, respectively). The mean cell numbers in blastocyst were significantly increased in GM-CSF supplemented groups compared to control group. LIF and IL-1beta expression in blastocysts were significantly higher in GM-CSF supplemented group than in control group. CONCLUSION: The results of experiment by mouse embryos showed beneficial effects of GM-CSF as a medium supplement. Furthermore, the addition of GM-CSF significantly increased the expression of LIF and IL-1beta in mouse embryos. These results suggest that GM-CSF might be a important molecule in embryo implantation.
Animals ; Blastocyst ; Cell Count ; Embryo Implantation ; Embryonic Development* ; Embryonic Structures* ; Female ; Granulocyte-Macrophage Colony-Stimulating Factor* ; Mice* ; Mice, Inbred ICR ; Oviducts ; Pregnancy ; RNA, Messenger

Stored maternal factors in oocytes regulate oocyte differentiation into embryos during early embryonic development. Before zygotic gene activation (ZGA), these early embryos are mainly dependent on maternal factors for survival, such as macromolecules and subcellular organelles in oocytes. The genes encoding these essential maternal products are referred to as maternal effect genes (MEGs). MEGs accumulate maternal factors during oogenesis and enable ZGA, progression of early embryo development, and the initial establishment of embryonic cell lineages. Disruption of MEGs results in defective embryogenesis. Despite their important functions, only a few mammalian MEGs have been identified. In this review we summarize the roles of known MEGs in mouse fertility, with a particular emphasis on oocytes and early embryonic development. An increased knowledge of the working mechanism of MEGs could ultimately provide a means to regulate oocyte maturation and subsequent early embryonic development.
Animals ; Cell Lineage ; Embryonic Development* ; Embryonic Structures ; Female ; Fertility ; Mice* ; Oocytes ; Oogenesis ; Organelles ; Pregnancy ; Transcriptional Activation

Retinoic acid(RA), formed in vivo by oxidation of retinol, is known as morphogenic signal. RA plays an active role in normal embryonic development at physiological concentration, but excess RA can be a powerful teratogen in human and animals. The present study was designed to examine the direct effect of RA on murine embryogenesis(gastrulation) and to define the specific development processes perturbed by RA. Five to fifteen blastocysts were randomly assigned to separate culture dishes of the experimental group. Various concentrations of RA(10(-9) M, 10(-7) M, and 10(-5) M) were used in culturing blastocysts. In the effect of RA on the normal grouwth of embryo, the rates of development to the stages of attachment, early egg cylinder(EEC), late egg cylinder(LEC), and early somite(ES)were significantly(p < 0.01) decreased as the RA concentration increased. Stil in the yolk sac formation rate, there was a significant, dose-dependent difference(p < 0.01) according to the RA concentration. In the degeneration of embryos by RA, the effect was more apparent as the concentration of Ra increased. The production rates of embryos devoid of egg cylinder region and embryos with abnormal egg cylinder region were increased (p < 0.01)in a dose-dependent manner according to RA concentration. In conclusion, RA probably act as teratogen at gastrula stage embryos in high concentration and effect of teratogenesis is dose-dependent.
Animals ; Blastocyst ; Embryonic Development ; Embryonic Structures ; Female ; Gastrula ; Gastrulation* ; Humans ; Mice* ; Ovum ; Pregnancy ; Teratogenesis ; Tretinoin* ; Vitamin A ; Yolk Sac

OBJECTIVETo test whether intracytoplasmic injection of morphologically selected spermatozoa (IMSI) from patients with male factor infertility can improve the clinical and embryo development outcomes of intracytoplasmic sperm injection-embryo transfer (ICSI-ET).

METHODSWe performed IMSI for 82 couples diagnosed with obstructive azoospermia at high magnification (×6600) and traditional ICSI for another 91 couples using testicular sperms. We also performed IMSI for 44 couples with teratozoospermia at high magnification (×6600) and traditional ICSI for 71 patients using ejaculated sperms. The clinical and embryo development outcomes were compared between the cycles.

RESULTSFor obstructive azoospermia, IMSI and ICSI showed no significant difference in the rates of cleavage (95.5% vs 96.7%), D3 top quality embryos (28.2% vs 29.2%), implantation (26.4% vs 32.3%), pregnancy (47.3% vs 50%), blastocyst formation (54.3% vs 54.6%), or abortion (14% vs 7.3%) (P>0.05), but a significantly higher normal fertilization rate was achieved in IMSI group (84.3% vs 77%, P<0.05). For teratozoospermia, the 2 techniques resulted in no significant differences in the rates of cleavage (96.2% vs 95.2%), D3 top quality embryo (27.6% vs 27.1%), implantation (28.2% vs 30.7%), pregnancy (43.7% vs 43.2%), or abortion (9.7% vs 10.5%) (P>0.05), but the normal fertilization rate (68% vs 75.5%) and the blastocyst formation rate (54.6% vs 67.9% ) were significantly higher in IMSI group (P<0.05).

CONCLUSIONIMSI can improve the normal fertilization rates in couples with male factor infertility (including obstructive azoospermia and teratozoospermia) and increase blastocyst formation rate in cases of azoospermia.

Embryo Implantation ; Embryo Transfer ; Embryonic Development ; Female ; Fertilization ; Humans ; Infertility, Male ; therapy ; Male ; Pregnancy ; Sperm Injections, Intracytoplasmic ; Spermatozoa ; cytology ; Treatment Outcome

OBJECTIVETo investigate the influence of the DNA integrity of optimized sperm on the embryonic development and clinical outcomes of in vitro fertilization and embryo transfer (IVF-ET).

METHODSThis study included 605 cycles of conventional IVF-ET for pure oviductal infertility performed from January 1, 2013 to December 31, 2014. On the day of retrieval, we examined the DNA integrity of the sperm using the sperm chromatin dispersion method. According to the ROC curve and Youden index, we grouped the cycles based on the sperm DNA fragmentation index (DFI) threshold value for predicting implantation failure, early miscarriage, and fertilization failure, followed by analysis of the correlation between DFI and the outcomes of IVF-ET.

RESULTSAccording to the DFI threshold values obtained, the 605 cycles fell into four groups (DFI value < 5%, 5-10%, 10-15%, and ≥ 15%). Statistically significant differences were observed among the four groups in the rates of fertilization, cleavage, high-quality embryo, implantation, clinical pregnancy, early miscarriage, and live birth (P < 0.05), but not in the rates of multiple pregnancy, premature birth, and low birth weight (P > 0.05). DFI was found to be correlated negatively with the rates of fertilization (r = -0.32, P < 0.01), cleavage (r = -0.19, P < 0.01), high-quality embryo (r = -0.40, P < 0.01), clinical pregnancy (r = -0.20, P < 0.01), and live birth (r = -0.09 P = 0.04), positively with the rate of early miscarriage (r = 0.23, P < 0.01), but not with the rates of multiple pregnancy (r = -0.01, P = 0.83), premature birth (r = 0.04, P = 0.54), and low birth weight (r = 0.03, P = 0.62).

CONCLUSIONThe DNA integrity of optimized sperm influences fertilization, embryonic development, early miscarriage, and live birth of IVF-ET, but its correlation with premature birth and low birth weight has to be further studied.

Abortion, Spontaneous ; Chromatin ; ultrastructure ; DNA Fragmentation ; Embryo Implantation ; Embryo Transfer ; Embryonic Development ; Female ; Fertilization ; Fertilization in Vitro ; Humans ; Infertility, Female ; Male ; Pregnancy ; Pregnancy Outcome ; ROC Curve ; Spermatozoa ; cytology

Angiotensin-converting enzyme functions in the male reproductive system, but the extent of its function in reproduction is not fully understood. The primary objective of this work was to investigate the relationship between the testicular isoform of angiotensin-converting enzyme present in human spermatozoa and semen parameters, human embryo quality, and assisted reproduction success. A total of 81 semen samples and 635 embryos from couples undergoing oocyte donation cycles at the IVI Bilbao Clinic were analyzed. Semen parameters, embryos quality, and blastocyst development were examined according to the World Health Organization standards and the Spanish Association of Reproduction Biology Studies criteria. The percentage of testicular angiotensin-converting enzyme-positive spermatozoa and the number of molecules per spermatozoon were analyzed by flow cytometry. Both parameters were inversely correlated with human sperm motility. Higher percentages of testicular angiotensin-converting enzyme-positive spermatozoa together with fewer enzyme molecules per spermatozoon were positively correlated with better embryo quality and development. Our results suggest that embryos with a higher implantation potential come from semen samples with higher percentages of testicular angiotensin-converting enzyme-positive cells and fewer enzyme molecules per spermatozoon. Based on these findings, we propose that testicular angiotensin-converting enzyme could be used to aid embryologists in selecting better semen samples for obtaining high-quality blastocysts during in vitro fertilization procedures.
Adult ; Embryo Implantation/physiology* ; Embryo Transfer ; Embryonic Development/physiology* ; Fertility/physiology* ; Fertilization in Vitro ; Humans ; Male ; Middle Aged ; Peptidyl-Dipeptidase A/metabolism* ; Sperm Motility/physiology* ; Spermatozoa/enzymology* ; Testis/enzymology*

OBJECTIVE: We evaluated the fertilization potential of immature oocytes obtained from controlled ovarian hyperstimulation cycles of patients undergoing ICSI. METHODS: We retrospectively analyzed 463 ICSI cycles containing at least one immature oocyte at oocyte denudation. ICSI was performed on mature oocytes at oocyte denudation (metaphase-II [MII] oocytes) and the oocytes that extruded the first polar body between oocyte denudation and ICSI (MI-MII oocytes). Fertilization and early embryonic development were compared between MII and MI-MII oocytes. To investigate the pregnancy potential of MI-MII oocytes, the pregnancy outcome was analyzed in 24 ICSI cycles containing only immature oocytes at retrieval. RESULTS: The fertilization rate of MI-MII oocytes (37.0%) was significantly lower than that of MII oocytes (72.3%). The rates of delayed embryos and damaged embryos did not significantly differ. Eighty-one immature oocytes were retrieved in 24 cycles that retrieved only immature oocytes and 61 (75.3%) of them were in the MI stage. ICSI was performed on 36 oocytes (59.0%) that extruded the first polar body before ICSI and nine MI-MII oocytes (25.0%) were fertilized. Embryo transfers were performed in five cycles. Pregnancy was observed in one cycle, but it ended in biochemical pregnancy. CONCLUSION: In ICSI cycles, oocytes that extruded the first polar body between denudation and ICSI can be used as a source of oocytes for sperm injection. However, their fertilization and pregnancy potential are lower than that of mature oocytes. Therefore, ovarian stimulation should be performed carefully for mature oocytes obtained at retrieval, especially in cycles with a small number of retrieved oocytes.
Embryo Transfer ; Embryonic Development ; Embryonic Structures ; Female ; Fertilization ; Humans ; Oocytes ; Ovulation Induction ; Polar Bodies ; Pregnancy ; Pregnancy Outcome ; Retrospective Studies ; Sperm Injections, Intracytoplasmic ; Spermatozoa