Effect of laser artificial shrinkage on pregnancy outcome in vitrification of human expanded blastocysts / 西安交通大学学报(医学版)

Objective To investigate the effect of laser artificial shrinkage(LAS)on pregnancy outcome in vitrification of human expanded blastocysts.Methods We selected 3859 frozen-thawed blastocyst-stage embryo transfers from January 2014 to December 2015.The transfers were divided into LAS group(n=3 176)and non-LAS group(n=683),which were then subdivided into ＜36 y subgroup and ≥36 y subgroup according to their age.Main outcomes measures were thawing rate,implantation rate and clinical pregnancy rate.Results Thawing rate, clinical pregnancy rate and implantation rate were 97.32%(5 453/5 603),66.81%(2 118/3 170),and 53.55%(2 912/5 438)in LAS group.In non-shrink group,they were 95.13%(1 173/1 233),62.70%(427/681),and 49.74%(582/1 170),which did not significantly differ from those in the former group(P＜0.05).Further analysis of the subgroups showed that thawing rate was significantly higher in LAS group than in non-shrink group of patients＜36 y(97.27% vs.95.33%;P＜0.05).Thawing rate and biochemical pregnancy rate were significantly higher in LAS group than in non-shrink group in patients ≥36 y(97.75% vs.93.66%;65.45% vs.50.65%,P＜0.05). Cancellation rate was not significantly different between the two groups(0.19% vs.0.29%, P ＞ 0.05). Conclusion LAS technique can increase thawing rate,clinical pregnancy rate and implantation rate before cryopreservation of blastocysts.

The effect of artificial shrinkage and assisted hatching on the development of mouse blastocysts and cell number after vitrification / 대한생식의학회지

OBJECTIVE: The goal of this study was to ascertain optimal assisted hatching (AH) method in frozen embryo transfer. We compared the effect of depending on whether mechanical or laser-AH was performed before or after the vitrification of embryo development rate and blastocyst cell numbers. METHODS: In order to induce superovulation, pregnant mare's serum gonadotropin followed by human chorionic gonadotropin were injected into 4- to 5-week-old female mice. 2-cell embryos were then collected by flushing out the oviducts. The Expanded blastocysts were recovered after the collected embryos were incubated for 48 hours, and were then subjected to artificial shrinkage (AS) and cross-mechanical AH (cMAH) or quarter-laser zona thinning-AH (qLZT-AH) were carried out using the expanded blastocysts before or after vitrification. After 48 hours of incubation, followed by vitrification and thawing (V-T), and blastocysts were fluorescence stained and observed. RESULTS: The rate of formation of hatched blastocysts after 24 and 72 hours of incubation was significantly higher in the AS/qLZT-AH/V-T group than in the other groups (p<0.05). The cell number of the inner cell mass was higher in AS/V-T/non-AH and AS/V-T/cMAH groups than those of others (p<0.05). In the control group, the number of trophectoderm and the total cell number were higher than in the AS-AH group (p<0.05). CONCLUSION: The above results suggest that AS and AH in vitrification of expanded blastocysts lead to the more efficient formation of hatched blastocysts in mice.

Vitrification solution without sucrose for cryopreservation in mouse blastocysts / 대한생식의학회지

OBJECTIVE: This study was designed to investigate the survival rate of vitrified mouse blastocysts depending on the presence or absence of sucrose in vitrification solution. METHODS: Mouse two-cell embryos were collected and cultured to blastocysts. Two vitrification solutions were prepared. The control solution was composed of 25% glycerol, 25% ethylene glycol, and 0.5 M sucrose (G25E250.5S) containing 2.5 mL glycerol, 2.5 mL ethylene glycol, 2 mL SSS, and 0.855 g sucrose in 5 mL PB1. The experimental solution was composed of 25% glycerol and 25% ethylene glycol (G25E25) and contained 2.5 mL glycerol and 2.5 mL ethylene glycol in 5 mL PB1. Artificial shrinkage was conducted by aspirating the blastocoelic fluid using an ICSI pipette. To examine the effect of sucrose in the vitrification solution on the survival rate of mouse blastocysts, the shrunken-equilibrated blastocysts were rehydrated or vitrified after being exposed to one of the two vitrification solutions. After exposure and the vitrification-thawing process, the re-expansion rate and hatching rate were evaluated after 6 hours of in vitro culture. RESULTS: The re-expansion rate of mouse blastocysts exposed to vitrification solution with and without sucrose were not different in the experimental solution (without sucrose) (98%) and the control solution (with sucrose) (92%) (p>0.05). The hatching rate was higher in the experimental solution (95%) than in the control solution (88%), but did not differ across two treatments (p>0.05). The re-expansion rate of mouse blastocysts vitrified in the control solution was 92% and 94%, respectively (p>0.05), and the hatching rate was higher in the experimental solution (90%) than in the control solution (74%) (p<0.05). CONCLUSION: Sucrose need not be added in vitrification solution for freezing of artificially shrunken mouse blastocysts.

Effect of artificial shrinkage on clinical outcome in fresh blastocyst transfer cycles / 대한생식의학회지

OBJECTIVE: This study aimed to determine the safety and clinical effect of artificial shrinkage (AS) in terms of assisted hatching of fresh blastocysts. Also, we evaluated the correlation between patient age and the effect of AS on clinical outcome. METHODS: Two AS methods, using a 29-gauge needle and laser pulse, were compared. Seventy-three blastocysts were shrunk using a 29-gauge needle and the same number of other blastocysts were shrunk by a laser pulse. We evaluated the shrunken blastocysts hourly and considered them viable if they re-expanded >70%. Blastocyst transfer cycles (n=134) were divided into two groups: a control group consisted of the cycles whose intact embryos were transferred (n=100), while the AS group consisted of the cycles whose embryos were replaced following AS (n=34). The implantation and pregnancy rates of the control group and AS group were compared (p<0.05). RESULTS: The re-expansion rates of the 29-gauge needle and laser pulse AS groups were similar (56 [76.7%] vs. 62 [84.9%], respectively). All of the remaining shrunken blastocysts were re-expanded within 2 hours. There was no degeneration of shrunken blastocysts. The total and clinical pregnancy rate of the AS group (23 [67.6%]; 20 [58.8%], respectively) was significantly higher than that of the control group (47 [47.0%]; 39 [39.0%], respectively). In the older patient group, there was no difference in the clinical outcomes between the AS and control groups. CONCLUSION: These results suggest that AS of blastocoele cavity, followed by the transfer, would be a useful approach to improve the clinical outcome in cycles in which fresh blastocyst stage embryos are transferred.