Abstract：
OBJECTIVE: To determine whether oxygen (O2) tension (20% vs. 5%) has an impact on oocyte maturation rates and morphology during in vitro maturation (IVM).
METHODS: A prospective, observational, monocentric, sibling-oocyte study.
METHODS: University Hospital.
METHODS: A total of 143 patients who underwent IVM for fertility preservation purposes from November 2016 to April 2021 were analyzed. Patients were included when ≥2 cumulus-oocyte complexes (COCs) were retrieved. The cohort of COCs obtained for each patient was randomly split into two groups: group 20% O2 and group 5% O2.
METHODS: Cumulus-oocyte complexes were incubated for 48 hours either under 5% O2 or 20% O2. After 24 and 48 hours of culture, every oocyte was assessed for maturity and morphology, to estimate oocyte quality. Morphology was evaluated considering six parameters (shape, size, ooplasm, perivitelline space, zona pellucida, and polar body characteristics), giving a total oocyte score ranging from -6 to +6.
METHODS: Maturation rates and total oocyte scores were compared using paired-sample analysis between group 20% O2 and group 5% O2.
RESULTS: Patient median age was 31.4 [28.1-35.2] years-old. The mean serum antimüllerian hormone levels and antral follicle count were 3.2 ± 2.3 ng/mL and 27.2 ± 16.0 follicles, respectively. A mean of 10.7 COCs per cycle were retrieved, leading to 6.1 ± 2.4 metaphase II oocytes vitrified (total maturation rate = 57.3%; 991 metaphase II oocytes/1,728 COCs). A total of 864 COCs were included in each group. Oocyte maturation rates were not different between the two groups (group 20% O2: 56.82% vs. group 5% O2: 57.87%, respectively). Regarding oocyte morphology, the mean total oocyte score was significantly higher in group 5% O2 compared with group 20% O2 (3.44 ± 1.26 vs. 3.16 ± 1.32, P=.014).
CONCLUSIONS: As culture under low O2 tension (5% O2) improves oocyte morphology IVM, our results suggest that culture under hypoxia should be standardized. Additional studies are warranted to assess the impact of O2 tension on oocyte maturation and the benefit of IVM under low O2 tension for embryo culture after utilization of frozen material.
METHODS: A prospective, observational, monocentric, sibling-oocyte study.
METHODS: University Hospital.
METHODS: A total of 143 patients who underwent IVM for fertility preservation purposes from November 2016 to April 2021 were analyzed. Patients were included when ≥2 cumulus-oocyte complexes (COCs) were retrieved. The cohort of COCs obtained for each patient was randomly split into two groups: group 20% O2 and group 5% O2.
METHODS: Cumulus-oocyte complexes were incubated for 48 hours either under 5% O2 or 20% O2. After 24 and 48 hours of culture, every oocyte was assessed for maturity and morphology, to estimate oocyte quality. Morphology was evaluated considering six parameters (shape, size, ooplasm, perivitelline space, zona pellucida, and polar body characteristics), giving a total oocyte score ranging from -6 to +6.
METHODS: Maturation rates and total oocyte scores were compared using paired-sample analysis between group 20% O2 and group 5% O2.
RESULTS: Patient median age was 31.4 [28.1-35.2] years-old. The mean serum antimüllerian hormone levels and antral follicle count were 3.2 ± 2.3 ng/mL and 27.2 ± 16.0 follicles, respectively. A mean of 10.7 COCs per cycle were retrieved, leading to 6.1 ± 2.4 metaphase II oocytes vitrified (total maturation rate = 57.3%; 991 metaphase II oocytes/1,728 COCs). A total of 864 COCs were included in each group. Oocyte maturation rates were not different between the two groups (group 20% O2: 56.82% vs. group 5% O2: 57.87%, respectively). Regarding oocyte morphology, the mean total oocyte score was significantly higher in group 5% O2 compared with group 20% O2 (3.44 ± 1.26 vs. 3.16 ± 1.32, P=.014).
CONCLUSIONS: As culture under low O2 tension (5% O2) improves oocyte morphology IVM, our results suggest that culture under hypoxia should be standardized. Additional studies are warranted to assess the impact of O2 tension on oocyte maturation and the benefit of IVM under low O2 tension for embryo culture after utilization of frozen material.
摘要：
目的：确定氧气张力（20％对5％）是否对体外成熟过程中的卵母细胞成熟率和形态有影响。
方法：前瞻性，观察,单心,兄弟姐妹卵母细胞研究。
方法：对2016年11月至2021年4月为保存生育力而进行体外成熟的143例患者进行分析。当检索到≥2个卵丘-卵母细胞复合物时，包括患者。每位患者获得的卵丘-卵母细胞复合物队列随机分为两组:20%O2组和5%O2组。
方法:卵丘-卵母细胞复合物在5%O2或20%O2下孵育48小时。培养24h和48h后，评估每个卵母细胞的成熟度和形态，估计卵母细胞质量。考虑6个参数(形状，尺寸,卵质,卵黄膜周围空间,透明带和极体特征)，给出总卵母细胞评分范围从-6到+6。
方法：使用配对样本分析比较20%O2组和5%O2组的成熟率和卵母细胞总评分。
结果：患者中位年龄为31.4岁[28.1-35.2]。平均血清AMH水平和窦卵泡计数为3.2±2.3ng/mL和27.2±16.0个卵泡，分别。检索到每个周期平均10.7个卵丘-卵母细胞复合物，导致6.1±2.4中期II卵母细胞玻璃化（总成熟率=57.3％；991中期II卵母细胞/1728卵丘-卵母细胞复合物）。每组共包括864个卵丘-卵母细胞复合物。两组之间的卵母细胞成熟率没有差异（组20％O2：56.82％vs.5%O2组:57.87%,分别,P=0.27）。关于卵母细胞形态，与20%O2组相比，5%O2组的平均卵母细胞总评分明显更高(3.44±1.26vs.3.16±1.32,P=0.014)。
结论：因为低氧张力（5％O2）下的培养改善了体外成熟过程中的卵母细胞形态，我们的结果提示低氧培养应标准化.有必要进行其他研究，以评估氧气张力对卵母细胞成熟的影响以及利用冷冻材料后在低氧张力下体外成熟对胚胎培养的益处。
方法：前瞻性，观察,单心,兄弟姐妹卵母细胞研究。
方法：对2016年11月至2021年4月为保存生育力而进行体外成熟的143例患者进行分析。当检索到≥2个卵丘-卵母细胞复合物时，包括患者。每位患者获得的卵丘-卵母细胞复合物队列随机分为两组:20%O2组和5%O2组。
方法:卵丘-卵母细胞复合物在5%O2或20%O2下孵育48小时。培养24h和48h后，评估每个卵母细胞的成熟度和形态，估计卵母细胞质量。考虑6个参数(形状，尺寸,卵质,卵黄膜周围空间,透明带和极体特征)，给出总卵母细胞评分范围从-6到+6。
方法：使用配对样本分析比较20%O2组和5%O2组的成熟率和卵母细胞总评分。
结果：患者中位年龄为31.4岁[28.1-35.2]。平均血清AMH水平和窦卵泡计数为3.2±2.3ng/mL和27.2±16.0个卵泡，分别。检索到每个周期平均10.7个卵丘-卵母细胞复合物，导致6.1±2.4中期II卵母细胞玻璃化（总成熟率=57.3％；991中期II卵母细胞/1728卵丘-卵母细胞复合物）。每组共包括864个卵丘-卵母细胞复合物。两组之间的卵母细胞成熟率没有差异（组20％O2：56.82％vs.5%O2组:57.87%,分别,P=0.27）。关于卵母细胞形态，与20%O2组相比，5%O2组的平均卵母细胞总评分明显更高(3.44±1.26vs.3.16±1.32,P=0.014)。
结论：因为低氧张力（5％O2）下的培养改善了体外成熟过程中的卵母细胞形态，我们的结果提示低氧培养应标准化.有必要进行其他研究，以评估氧气张力对卵母细胞成熟的影响以及利用冷冻材料后在低氧张力下体外成熟对胚胎培养的益处。
