The association of follicular fluid volume with human oolemma stretchability during intracytoplasmic sperm injection

Abstract

ObjectiveOocyte degeneration often occurs after intracytoplasmic sperm injection (ICSI), and the risk factor is low-quality oocytes. The follicular fluid (FF) provides a crucial microenvironment for oocyte development. We investigated the relationships between the FF volume aspirated from individual follicles and oocyte retrieval, oocyte maturity, oolemma stretchability, fertilization, and development.MethodsThis retrospective study included data obtained from 229 ICSI cycles. Ovarian stimulation was performed according to a gonadotropin-releasing hormone antagonist protocol. Each follicle was individually aspirated and divided into six groups according to FF volume (<1.0, 1.0 to <2.0, 2.0 to <3.0, 3.0 to <4.0, 4.0 to <5.0, and ≥5.0 mL). Oolemma stretchability during ICSI was evaluated using a mechanical stimulus for oolemma penetration, that is, the stretchability was assessed by oolemma penetration with aspiration (high stretchability) or without aspiration (low stretchability).ResultsOocyte retrieval rates were significantly lower in the <1.0 mL group than in the ≥1.0 mL groups (46.0% [86/187] vs. 67.5%–74.3% [172/255 to 124/167], respectively; p<0.01). Low oolemma stretchability was significantly more common in the <1.0 mL group than in the ≥1.0 mL groups during ICSI (22.0% [13/59] vs. 5.8%–9.4% [6/104 to 13/139], respectively; p=0.018). There was a relationship between FF volume and oolemma stretchability. However, there were no significant differences in the rates of fertilization, cleavage, ≥7 cells at day 3, and blastocyst development among all groups.ConclusionFF volume is potentially associated with the stretchability of metaphase II oolemma during ICSI. Regarding oolemma stretchability, ensuring a uniform follicular size during ovarian stimulation is crucial to obtain good-quality oocytes.

Association of follicular fluid volume with membrane stretchability of human metaphase II oocytes following the gonadotropin‐releasing hormone agonist protocol during intracytoplasmic sperm injection

“…Individual follicles were aspirated, as described previously . In brief, after measuring the diameter, each follicle was individually aspirated and collected.…”

“…Each individually obtained COC was placed into a 5 mL round‐bottomed tube (Falcon ® ; Corning, Inc.) containing 1 mL of HFF99 medium (Fuso Pharmaceutical Industries, Osaka, Japan) with 10% serum protein substitute (Kitazato Corporation) and then was cultured for 2‐3 hours until denudation. To prevent an over‐ or underestimation of the ellipsoid follicular diameter by two‐dimensional transvaginal ultrasonography, the FF volume was estimated carefully …”

“…The oocytes were inseminated through ICSI by using injection pipettes (inner diameter: 4.7 μm; outer diameter: 6.0 μm; Cook Medical, Bloomington, IN, USA) . The level of oolemma stretchability was evaluated, as described previously . In brief, the oolemma stretchability during ICSI was evaluated by using an additional mechanical stimulus for oolemma penetration; that is, with or without aspiration (high vs low stretchability, respectively).…”

“…The authors’ previous study demonstrated that the oolemma of human metaphase II (MII) oocytes from individual follicles with a low follicular fluid (FF) volume following the gonadotrophin‐releasing hormone (GnRH) antagonist protocol were more likely to have a low stretchability during ICSI, suggesting a potential association between the FF volume with oolemma stretchability . However, the relationship between MII oolemma stretchability following the GnRH agonist protocol and the FF volume remains unclear.…”

“…The aim of this study was to investigate the relationship between the FF volume that was aspirated from individual follicles and oocyte retrieval, oocyte maturity, the cumulus‐oocyte complex (COC) grade, oolemma stretchability, fertilization, and embryonic development following the administration of a short GnRH agonist protocol, according to the outcome measures in the authors’ previous GnRH antagonist study …”