Shanjun Dai

Effect of coincubation time of sperm-oocytes on fertilization, embryonic development, and subsequent pregnancy outcome

Several studies have reported improved IVF by shortening the time of sperm-oocyte coincubation from 16–18 hours to 1–4 hours. The objective of this study was to examine the advantages and disadvantages of a shortened sperm-oocyte coincubation time in order to assess the effects of this insemination method for clinical IVF practice. Two insemination methods, the shortened method (4 hours) and the standard method (16–18 hours) of coincubation of sperm-oocytes for two groups of patients based on the quality of sperm were compared. Group I, was composed of couples without male factor; Group II, involved couples with mild male factor. Fertilization, good quality embryos, clinical pregnancy, and implantation rates were compared by two different insemination methods. In Group I, fertilization, clinical pregnancy, and implantation rates were not different between the two insemination methods. However, the polyspermy rate was significantly higher (P < 0.05) in the shortened (7.3%) than in the standard (4.1%) insemination method. In Group II, the fertilization rate was significantly lower (P < 0.05) using the shortened insemination method (62.6%) compared to the standard insemination method (68.7%). When fertilization failed with the shortened insemination method, the clinical pregnancy and implantation rates were 34.7% and 24.1%, respectively, from the rescue intracytoplasmic sperm injection (ICSI). The live birth rate from the rescue ICSI was 32.0% with normal infants. The duration of sperm-oocyte coincubation does not affect fertilization, embryo quality, clinical pregnancy, and implantation rates. However, fertilization rates will decrease with the shortened insemination method when the sperm parameters are poor. From the results of the present study we suggest that the combination of the shortened sperm-oocyte coincubation and rescue ICSI method may be an efficient method for IVF treatment in order to prevent fertilization failure when sperm parameters were poor as mild male factor.

Embryo developmental potential of microsurgically corrected human three-pronuclear zygotes

Abstract We explored the embryo development potential of human three-pronuclear (3PN) zygotes reduced to two-pronuclear (2PN) zygotes (3 → 2PN zygotes) by micropuncture. In this study, there were three groups, the 3 → 2PN group (338 zygotes), the non-corrected 3PN group (381 zygotes), and the normal 2PN group (359 zygotes). The first cleavage mode (2-cell cleavage or 3-cell cleavage), 6–8 cell embryogenesis rate, high-quality embryogenesis rate and Day 5/Day 6 blastulation rate were compared between the three groups. The success rate of enucleation was 92.9%. The 2-cell cleavage rate was significantly higher in the 3 → 2PN group (74.3%) than in the 3PN group (36.4%) (P < 0.05), but had no statistical difference compared with the 2PN group (86.0%) (P > 0.05). The 6–8 cell embryogenesis rate was significantly higher in the 3 → 2PN group (91.1%) as compared to the 2PN group (85.6%) (P < 0.05), but had no statistical difference compared with the 3PN group (95.0%) (P > 0.05). Total blastulation rate was significantly higher in the 2PN group (58.8%) as compared to the 3PN group (21.5%) (P < 0.01), and in the 3 → 2PN group as compared to the 3PN group (5.6%) (P < 0.01). Also D5 blastulation rate was significantly higher in the 2PN group (53.7%) as compared to the 3 → 2PN group (8.9%) (P < 0.01), and in the 3 → 2PN group as compared to the 3PN group (1.9%) (P < 0.01). In 3 → 2PN zygotes, the first cleavage mode is mainly 2 cells which is significantly higher than that in 3PN zygotes. Compared with 3PN zygotes, the embryo developmental potential of 3 → 2PN zygotes is improved, but still is lower than that in 2PN zygotes.

Shorter leukocyte telomere length is associated with risk of nonobstructive azoospermia

OBJECTIVE To determine the association between leukocyte telomere length and the risk of nonobstructive azoospermia (NOA). DESIGN The mean leukocyte telomere length (LTL) among men with NOA, obstructive azoospermia (OA), and normospermic subjects was determined by quantitative polymerase chain reaction (PCR). We used logistic regression to investigate the association between LTL and the risk of NOA after adjustment for age and body mass index (BMI). Partial correlation analysis was also used to evaluate the relationship of clinical parameters with the mean LTL among men with OA and NOA. SETTING Reproductive medicine center. PATIENTS(S) A total of 866 men, including 270 normospermic controls, 247 OA and 349 NOA patients. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Leukocyte telomere length. RESULT(S) The mean relative LTL of men with NOA was significantly shorter than that of those with OA and in normospermic controls (odds ratio [OR] 0.81, 95% confidence interval [CI] 0.64-0.98 vs. OR 0.92, 95% CI 0.70-1.24 vs. OR 0.99, 95% CI 0.83-1.22), respectively). Subjects with shorter telomeres (lowest tertile) had a significantly higher risk of NOA than those with longer telomeres (highest tertile). Interestingly, we also found that a low relative LTL was associated with poor efficiency of spermatogenesis using the Johnsen score after testis biopsy and histopathology in azoospermic patients, after adjusting for patient age and BMI. CONCLUSION(S) This is the first report that short LTL is associated with NOA, shedding light on an important biological pathway involved in the etiology of this form of male factor infertility.