Frozen embryo transfer combined with intrauterine administration of autologous peripheral blood mononuclear cells for repeated implantation failure: report of 3 cases / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the efficacy of frozen-thawed embryo transfer combined with intrauterine administration of autologous peripheral blood mononuclear cells (PBMCs) in the treatment of repeated implantation failure (RIF).</p><p><b>METHODS</b>PBMCs obtained from 3 patients with RIF on the day of follicle rupture (natural cycle) or when the endometrial thickness reached 8 mm (hormone replacement cycle) were cultured in the presence of HCG for 48 h. The cultured PBMCs, along with freshly isolated PBMCs, were administered into the uterine cavity of the patients. Vitrified cleavage-stage embryos or blastocysts transfer was performed on day 3 or 5, respectively.</p><p><b>RESULTS</b>Vitrified embryo or blastocyst transfer resulted in pregnancy and healthy live births in all the 3 patients.</p><p><b>CONCLUSION</b>Frozen-thawed embryo transfer combined with intrauterine administration of autologous PBMCs may be an effective and safe approach to the treatment of RIF and may improve the outcomes of assisted reproduction.</p>

Relation between insulin resistance and insulin receptor gene methylation in the endometrium of patients with polycystic ovary syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the relationship between insulin resistance and methylation of insulin receptor (INSR) gene in the endometrium of women with polycystic ovary syndrome (PCOS).</p><p><b>METHODS</b>Based on the HOMA index, 35 patients with PCOS were divided into insulin resistant group (IR group, n=18) and non-resistant group (NIR group, n=18). The patients age, serum estriol, testosterone, FSH and LH, fasting insulin and fasting blood glucose were compared between the two groups. The endometrial samples were obtained from the patients to examine DNA methylation status of INSR gene in the endometrial cells using methylation-specific PCR.</p><p><b>RESULTS</b>The BMI, WHR, fasting glucose, fasting insulin, and HOMA index differed significantly between the two groups (P<0.05). PCR analysis showed partial methylation in the promoter region of INSR gene in 13 samples in IR group and 11 samples in NIR group, without detection of full methylation of the INSR gene in either group. The methylation status showed no significant difference between the two groups (P=0.328).</p><p><b>CONCLUSION</b>Partial methylation of the INSR gene occurs in the endometria of PCOS patients, but this study does not provide a strong evidence supporting the relationship between insulin resistance and INSR gene methylation in women with PCOS.</p>

CA 125 expression in cervical and vaginal secretions in women in normal reproductive period / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the tumor-associated antigen CA125 expression in the serum and cervical and vaginal secretions in women during normal reproductive period, and explore the clinical value of detecting tumor markers in the cervical and vaginal secretions.</p><p><b>METHODS</b>A total of 145 women in reproductive period were divided into 3 age groups (20-29 years, 30-39 years, and over 40 years), and their CA125 levels in cervical secretion, vaginal secretion and serum were detected by automatic electro-chemiluminescent immunoassay.</p><p><b>RESULTS</b>CA125 levels in the cervical secretion, vaginal secretion and serum showed no significant difference between the 3 age groups (P>0.05). In each group, CA125 levels differed significantly between the cervical secretion, vaginal secretion and serum (P<0.001). In the 145 women, the average CA125 level was 497.82 - or + 75.29 U/ml in the cervical secretion, 114.66 - or + 26.40 U/ml in vaginal secretion and 18.06 - or + 3.35 U/ml in serum, showing significant differences between them (P<0.001).</p><p><b>CONCLUSION</b>CA125 expression level is significantly higher in the cervical and vaginal secretions than in the serum in women in normal reproductive period, and its levels in cervical and vaginal secretions can be more sensitive and convenient for early detection of related diseases.</p>

Inhibitory effect of RNA interference targeting BaxBak on apoptosis of human granulosa cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the inhibitory effect of small interfering RNA (siRNA) targeting Bax-Bak on the apoptosis of human granulosa cells.</p><p><b>METHODS</b>Human granulosa cells were transfected with Bax-siRNA and Bak-siRNA either alone or in comibnation, and the cell morphological changes were obsered and the cell apoptosis was detected with flow cytometry. Western blotting was performed to examine the changes in Bax and Bak expressions in the transfected cells.</p><p><b>RESULTS</b>Western blotting demonstrated significantly weakened expressions of Bax and Bak in the transfected cells. The cell morphology of the cells tranfected with Bak siRNA and with both Bak and Bax siRNA remained normal; the cells with exclusive Bax siRNA transfection presented with basically normal cell morphology, but black spots were noted in the cytoplasm. In the positive and negative control groups, the cells became rounded and shrank with expanded intercellular spaces and numerous black spots in the cytoplasm. Flow cytometry showed apoptotic indexes of 3.44% and 3.97% in cells transfected with Bak siRNA and Bax-Bak siRNA, respectively, significantly lower than that in the negative group. Bax siRNA transfection resulted in an apoptotic index of 19.98%, similar to that in the negative group.</p><p><b>CONCLUSION</b>Interference of the expression of Bak gene inhibits the apoptosis of human granulosa cells, and the inhibitory effect can be enhanced by simultaneous Bax interference, which, when used alone, does not obviosuly inhibit the apoptosis of human granulosa cells.</p>

Clinical application of prefilled pen and conventional syringe during controlled ovarian stimulation for in vitro fertilization / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the efficacy, convenience and costs of recombinant follitropin alpha administered by a prefilled pen device and conventional syringe in Chinese women undergoing controlled ovarian stimulation for in vitro fertilization (IVF).</p><p><b>METHODS</b>A total of 184 patients undergoing IVF treatment were enrolled in this study. According to a long-term recombinant follicle-stimulating hormone (rFSH) protocol, ovarian stimulation was performed with the prefilled pen and conventional syringe at random in these subjects, and the dose of follitropin, number of oocytes and embryo parameters and IVF-ET outcome were compared between the two groups.</p><p><b>RESULTS</b>The total rFSH dose, cost, and frequency of hospital visits were significantly lower in the pen protocol group, but the residual rFSH amount was higher. Compared with conventional injections, the prefilled pen was associated with significantly lowered rate of local redness, high rate of local bruise, more frequent follitropin dose modulation and lower serum oestradiol levels on HCG day. No significant difference was found in the endometrial thickness, numbers of oocytes retrieved, MII oocytes, transferred embryo, or the clinical pregnancy rates between the two groups. The ratio of MII oocytes, good quality embryo rates and implantation rates was significantly higher in the pen group with lower incidences of moderate and severe ovarian hyperstimulation syndrome.</p><p><b>CONCLUSION</b>The prefilled pen provides an easy, safe, effective and more patient-friendly means for controlled ovarian stimulation procedure in Chinese women, but more attention should be given to protocol optimization and patient education.</p>

Relationship between protein oxidation levels in the follicular fluid and the outcome parameters of in vitro fertilization-embryo transplantation / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the relationship between protein oxidation levels in the follicular fluid and the outcome parameters of in vitro fertilization-embryo transplantation (IVF-ET).</p><p><b>METHODS</b>The levels of advanced oxidation protein products (AOPP) in the follicular fluid were measured in 64 women with tubal infertility undergoing IVF-ET. The relationship between the AOPP levels and IVF-ET outcome parameters was analyzed.</p><p><b>RESULTS</b>AOPP levels showed significant inverse correlations between the proportion of mature oocytes (r=-0.401, P=0.001), fertilization rate (r=-0.257, P=0.045), cleavage rate (r=-0.290, P=0.024) and good embryo rate (r=-0.520, P=0.000). AOPP levels differed significantly between the groups with different retrieved oocyte numbers (F=3.851, P=0.027), being the lowest in women with 8 to 15 retrieved oocytes and the highest in those with retrieved oocytes below 8. The AOPP level in the non-pregnant women was significantly higher than that in the pregnant women (t=3.665, P=0.001). The AOPP levels also differed significantly with age (F=15.919, P=0.000), and the women >35 years of age had the highest level and those below 30 years had the lowest level.</p><p><b>CONCLUSION</b>Protein oxidative stress is present in the follicular fluid of women on IVF-ET cycles. High level of AOPP may have adverse effects on the oocytes and early embryonic development and may affect the outcome of IVF-ET.</p>

Effect of two different doses of letrozole in promoting ovulation in infertile women with polycystic ovarian syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of two different doses of letrozole in promoting ovulation in infertile women with polycystic ovarian syndrome (PCOS).</p><p><b>METHODS</b>Seventy-six PCOS infertile women undergoing intrauterine insemination (IUI) or with anovulation were divided into two groups and received oral letrozole at the daily dose of 2.5 (n=36) or 5.0 mg (n=40) from the 3rd to the 7th day of the menstrual cycle. Three days after discontinuation of the medication (the 10th day of the menstrual cycle ), ultrasound scanning was performed to monitor the follicle development. When the diameter of the biggest follicle reached 14 mm, the presence of luteinizing hormone (LH) was monitored; when LH positivity was detected, blood samples were drawn to test follicle-stimulating hormone (FSH), LH, estradiol (E2) and testosterone (T) levels. Human chorionic gonadotropin (hCG, 10 000 U) was then injected to induce ovulation.</p><p><b>RESULTS</b>The ovulation rate, stimulation follicle days, diameter of the biggest follicle on the day of LH positivity and the thickness of endometrium were all similar between the two groups (P>0.05). But in women receiving 5.0 mg letrozole, both the number of mature follicles and pregnancy rate were significantly higher than those in women having the half dose (P<0.05). The levels of FSH, LH, E2, and T on the third day of menstruation and on the day of HCG injection were similar between the two groups (P<0.05).</p><p><b>CONCLUSION</b>Letrozole at the dose of 5.0 mg/day produces higher pregnancy rate and more mature follicles in fertile women with PCOS.</p>

Function of F10 gene, a novel hydatidiform mole-related gene: a preliminary study / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the function of F10 gene, a novel hydaditiform mole-related gene.</p><p><b>METHODS</b>A549 cell line was transfected with the F10 gene of forward or reverse sequence or with the empty vector, respectively. The cellular mRNA was extracted after 24 h of transfection to screen for the differentially expressed genes among the 3 transfected and the control cells using differential display-polymerase chain reaction (ddPCR).</p><p><b>RESULTS</b>The bands representing differentially expressed genes were amplified from the cells, and the products were linked to T-Vector for sequence analysis. Several genes were screened by Blasting and their expressions were confirmed by fluorescent quantitative PCR.</p><p><b>CONCLUSION</b>F10 gene is functionally related to cell proliferation and apoptosis.</p>

Expression of trophinin in human oocytes and preimplantation embryos / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the significance of trophinin expression in human oocytes and preimplantation embryos.</p><p><b>METHODS</b>The expression of trophinin in 9 human oocytes, 16 blastomeres and 12 blastocysts were detected by indirect immunofluorescence assay and observed under laser scanning confocal microscope.</p><p><b>RESULTS</b>Human oocytes, blastomeres and blastocysts were all positive for trophinin expression, and the positivity intensified significantly in the course of the embryonic development (P<0.05).</p><p><b>CONCLUSION</b>Trophinin may play an important role in human embryo implantation by mediating homophilic adhesion between the embryo and the endometrium during the implantation window.</p>

Proteomics of follicular fluid in mature human follicles and antral follicles: a comparative study with laser desorption/ionization-time of flight-mass spectrometry / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the differentially expressed proteins between mature and antral follicles and identify the proteins crucial for follicle development and oocyte fertilization.</p><p><b>METHODS</b>Mature follicular fluids were obtained from 48 women after oocyte collection during in vitro fertilization (IVF), and antral follicular fluids were collected from 21 women by follicular puncture. The proteins in the follicular fluids were detected by surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS) and weak cation-exchange protein chip (WCX-2). The data were read with PBSII-C type protein chip reader and analyzed with Biomarker Wizard and Biomarker Patterns Software of Ciphergen Company.</p><p><b>RESULTS</b>In comparison with those in the antral follicular fluid, the concentration of 4 proteins were significantly different in mature follicular fluid, including two up-regulated and two down-regulated proteins.</p><p><b>CONCLUSION</b>Significant variation occurs in the proteomics of mature follicular fluid, and the differentially expressed proteins may have close relation to follicle development and oocyte fertilization.</p>

F10 gene knock-down mediated by RNA interference induces apoptosis of KLE cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the effect of short double-stranded RNA (dsRNA) on F10 gene expression in KLE cells and the effect of F10 knock-down on KLE cell apoptosis.</p><p><b>METHODS</b>The short dsRNA specifically targeting F10 gene prepared by in vitro transcription was transfected into KLE cells via lipofectamine 2000. The expression of F10 mRNA in the transfected KLE cells was detected by real-time quantitative RT-PCR, and the apoptosis of the cells was assayed by flow cytometry.</p><p><b>RESULTS</b>Real-time quantitative RT-PCR demonstrated that transfection of the KLE cells with the short dsRNA induced effective knock-down of F10 gene, and transfection of the cells with 20 nmol/L dsRNA for 48 h decreased the expression of F10 mRNA by 83%. Compared with the control, the apoptosis index of the transfected KLE cells increased from 0.36% to 8.91%.</p><p><b>CONCLUSION</b>F10 gene in KLE cells can be specifically knocked-down with dsRNA prepared by in vitro transcription, and the down-regulation of F10 gene induces apoptosis of KLE cells.</p>

Allogeneic leukocyte immunization combined with IVF-ET for treatment of infertility induced by recurrent spontaneous abortion / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of allogeneic leukocyte immunization combined with in vitro fertilization-embryo transfer (IVF-ET) for treatment of infertility induced by habitual abortion.</p><p><b>METHODS</b>Allogeneic leukocyte immunization was performed in 9 patients with infertility induced by habitual abortion, with another 9 patients undergoing IVF-ET without habitual abortion as the control group. All the patients were treated with long GnRH-a protocols. The infertility patients with recurrent spontaneous abortion history were immunized with lymphocytes from the husband for before IVF-ET and after clinical pregnancy.</p><p><b>RESULTS</b>The fertilization rates of the immunotherapy group and control group were 81.3% and 82.2%, respectively, showing no significant difference (P>0.05). Five patients in each group had clinical pregnancy, and a twin pregnancy occurred in the control group. The embryo implantation rates were also comparable between the two groups (22.7% vs 28.6%, P>0.05). All the fetuses resulted from IVF-ET developed normally and were healthily delivered.</p><p><b>CONCLUSION</b>Allogeneic leukocyte immunotherapy along with IVF-ET is effective for treatment of infertility resulting from recurrent spontaneous abortion.</p>

MMP-2/TIMP-2 expression in the trophoblasts of patients with gestational trophoblastic disease / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the role of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of MMP-2 (TIMP-2) in the pathogenesis, development and prognosis of gestational trophoblastic disease (GTD).</p><p><b>METHODS</b>In situ hybridization and immunohistochemistry were utilized for MMP-2/TIMP-2 mRNA and protein detection in normal chorion of women with early gestation, hydatidiform mole, invasive mole, or choricarcinoma.</p><p><b>RESULTS</b>The results revealed that specific staining for mRNA and protein of MMP-2 and the expression of TIMP-2 was reduced in normal chorion of early gestation. In GTD ranging from hydatidiform mole, invasive mole to choricarcinoma, MMP-2 expression tended to increase while TIMP-2 expression underwent an invert change. The positivity rate of MMP-2 and TIMP-2 in gestational trophoblastic tumor group was higher than that of the normal chorion of early gestation group and hydatiform mole group (P<0.05 and P<0.001, respectively).</p><p><b>CONCLUSION</b>A disrupted balance between the activation and inhibition of MMP-2 plays a critical role in the pathogenesis, progression and metastasis of GTD.</p>

Comparison of clinical outcomes of four protocols for frozen-thawed embryo transfer cycle / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the clinical outcome of 4 protocols of frozen-thawed embryo transfer cycle to select the optimal endometrial preparation method for frozen-thawed embryos transfer.</p><p><b>METHODS</b>A retrospective analysis of the 4 clinical protocols was conducted including natural cycle, down-regulated hormone replacement treatment (HRT) cycle, hMG cycle and natural cycle+hCG in endometrial preparation for 419 frozen-thawed embryos transfer cycle, and the clinical pregnancy rate, implantation rate, early abortion rate, ectopic pregnancy rate , ongoing pregnancy rate and delivery rate were compared between the 4 protocols.</p><p><b>RESULTS</b>There was no significant difference between the 4 groups with different clinical protocols in age, duration of infertility, reason of infertility, number of embryo transferred and endometrial thickness. The 4 protocols differed little in the implantation rate, clinical pregnancy rate, biochemical pregnancy rate, early abortion rate, ectopic pregnancy rate, ongoing pregnancy rate and delivery rate in the four clinical protocols.</p><p><b>CONCLUSION</b>The 4 clinical protocols for frozen-thawed embryos transfer all have favorable clinical outcome, and choice of a specific protocol should be made according to the a comprehensive consideration of the individual conditions of the patient.</p>

Relation of human zygote morphology and implantation of the transferred embryo / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between human embryo implantation rates and the zygote morphology and establish zygote morphologic indices that indicate the embryo implantation potential after in vitro fertilization and embryo transfer (IVF-ET).</p><p><b>METHODS</b>Sixty-two patients with IVF-ET were enrolled in this study, who were below 35 years of age with endometrium thickness no greater than 8 mm on the day of HCG injection. Embryo transfer was performed on day 3 after oocyte retrieval, and 30 patients with successful implantation of all the embryos transferred (implantation rate of 100%) were allocated into the implantation group, and the other 32 patients with implantation failure (implantation rate of 0) served as the control group. The zygote morphologic characteristics were analyzed for the pronuclei, nucleolar precursor bodies (NPB), polar body, cytoplasmic halo, color and granulation of the cytoplasm, and the results were compared between the two groups.</p><p><b>RESULTS</b>The implantation rate was significantly higher for embryos with the two pronuclei in close vicinity, central position of the pronuclei in the cytoplasm and comparable size of the two pronuclei. Embryos developed from zygotes with linear arrangement of 3 to 7 NPB in moderate sizes tented to have a higher implantation rate (P<0.05). The implantation rate could be obviously lowered when the cytoplasm contained excessive cytoplasmic granularity (P<0.05). The other morphologic characteristics of the embryos such as the polar bodies, color of the cytoplasm, cytoplasm halo, or vacuoles in the cytoplasm did not significantly impact on the implantation rate.</p><p><b>CONCLUSION</b>The morphology of the two pronuclei reflects the quality of the zygote and may help predict the developmental potential of the embryo chosen for transfer on day 3 in IVF.</p>

Uncoupling protein-2 expression in granular cells and embryo development in in vitro fertilization-embryo transfer cycle / 南方医科大学学报

<p><b>OBJECTIVE</b>To examine the expression of uncoupling protein-2 (UCP2) in the granular cell of women undergoing in vitro fertilization (IVF) and explore its role in embryo development.</p><p><b>METHODS</b>In this prospective study, the levels of UCP2 and reactive oxygen species (ROS) were measured by the chemiluminescence method in the granular cell of 53 women.</p><p><b>RESULTS</b>Women with low UCP2 level had higher ROS level, suggesting an inverse relationship between them (r=-0.578, P<0.01), and their oocyte development was impaired. Granular cells of elder women exhibited lowered UCP2 expression.</p><p><b>CONCLUSION</b>The granular cells increase UCP2 expression to suppress the elevation of intracellular ROS level through a feedback mechanism and therefore protect the oocytes against oxidative stress.</p>

Pituitary down-regulation and ovulation stimulation with gradually increased gonadotropin in controlled ovarian hyperstimulation / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the efficacy of ovulation stimulation protocol with gradual increment of gonadotropin in women with high ovarian response.</p><p><b>METHODS</b>A retrospective study was conducted between june 2005 and April 2006 in 70 women undergoing controlled ovarian hyperstimulation. The clinical outcomes of the women using gradual increment protocol were compared with those of women receiving other ovulation-stimulating protocols.</p><p><b>RESULTS</b>The mean number of large follicles (>or=14 mm) and retrieved oocytes on the day of retrival was significantly lower, but the duration of stimulation was significantly longer in the gradual increment group than in the control group. The rate of follicular puncture was also higher in the former group. The clinical pregnancy rate, total gonadotropin dosage, cancellation rate and incidence of ovarian hyperstimulation syndrome were similar for the two groups.</p><p><b>CONCLUSION</b>Ovulation stimulation protocol with gradually increased gonadotropin may provide a promising alternative for controlled ovarian hyperstimulation in women with a strong ovarian response.</p>

Relation between embryo transfer distance from the fundus and the pregnancy rate / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the association of embryo transfer distance from the fundus (TDF) with the clinical pregnancy rate (PR).</p><p><b>METHODS</b>Between January 2005 and September 2006, ultrasound (US)-guided embryo transfer was conducted in 610 women. TDF was measured by transabdominal US according to which the subjects were divided into 4 groups. The association between TDF and PR or between TDF and abnormal pregnancy was analyzed.</p><p><b>RESULTS</b>No significant differences in PR were observed among those 4 groups, but PR was the highest in the group with TDF >or=2 cm, and the lowest in the group 1 cm. The rate of early spontaneous abortion was higher in the group with TDF >or=2 cm.</p><p><b>CONCLUSION</b>TDF variation does not produce significant difference in PR, but the distance of 1.0-2.0 cm is recommended.</p>

Neonatal outcomes of pregnancy resulting from in vitro fertilization and embryo transfer: analysis of 1274 cases / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the neonatal outcomes of pregnancies resulting from in vitro fertilization and embryo transfer (IVF-ET) in relation to the occurrence of congenital malformations of the neonates.</p><p><b>METHODS</b>A total of 1274 infants born after IVF-ET were reviewed. The neonatal outcome was evaluated based on gestational weeks, body weight, congenital malformations, manner of spermatization, maternal age and multiple gestation.</p><p><b>RESULTS</b>IVF-ET resulted in 930 deliveries, giving birth to a total of 1274 newborns. Spontaneous delivery occurred in 115 cases (12.37%), with preterm birth in 224 cases (24.09%). Among these newborns, 363 (28.49%) had very low born weight (VLBW), 13 (1.02%) had congenital malformations, and neonatal mortality occurred in 15 cases (1.18%).</p><p><b>CONCLUSION</b>IVF increases the risks of twin pregnancies, preterm birth and VLBW, but does not increase the rate of congenital malformations and neonatal mortality. Intracytoplasmic sperm injection (ICSI) is at higher risk of congenital malformations. Maternal age and twin pregnancies are not associated with congenital malformations. IVF can be safe for treatment of infertility.</p>

Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry for proteomic analysis of seminal plasma in patients with delayed semen liquefaction / 南方医科大学学报

<p><b>OBJECTIVE</b>To identify the differentially expressed proteins in seminal plasma between subjects with normal fertility and those with delayed semen liquefaction by proteomic techniques.</p><p><b>METHODS</b>Semen samples of 6 patients with delayed semen liquefaction and 11 subjects with normal fertility (control group) were collected. Seminal plasma were separated and examined with surface-enhanced laser desorption/ionization time of flight mass spectrometry to compare the protein expressions between the two groups.</p><p><b>RESULTS</b>Compared with normal control group, 19 proteins were differentially expressed in the patients including 6 proteins with significant differences between the two groups, with m/z of 8696.621, 9770.076, 9512.309, 10202.64, 2941.903, and 9617.759, respectively (P<0.01).</p><p><b>CONCLUSION</b>Screening of differentially expressed proteins in seminal plasma may help understand the mechanism of delayed semen liquefaction for its potential clinical intervention.</p>