Ovarian tissue cryopreservation for patients with premature ovary insufficiency caused by cancer treatment: optimal protocol

Abstract

Objective: Premature ovary insufficiency is frequent after chemotherapy/radiotherapy in cancer patients. Ovarian tissue (OT) cryopreservation and later retransplantation, the routine method in Europe, has recently been implemented at the first center in China. We investigated the protective effect of the antioxidant N-acetyl-l-cysteine (NAC) during the decisive freezing–thawing steps.

Methods: Fifteen OT samples were obtained from each of 13 cancer patients prospectively and randomly assigned to a control group and four groups with different NAC concentrations (Group 1, 0 mM NAC; Group 2, 0.5 mM NAC; Group 3, 1 mM NAC; Group 4, 5 mM NAC; Group 5, 25 mM NAC). After thawing, the follicle viability, DNA fragmentation, levels of reactive oxygen species (ROS), and total antioxidant capacity (TAC) were evaluated.

Results: OT cryopreserved and thawed with 25 mM NAC (Group 5) has the lowest proportion of apoptotic stroma cells, but the worst follicle viability. The other four groups show similar anti-apoptosis and good follicle viability. Group 4 presented the lowest ROS and highest TAC levels.

Conclusions: OT cryopreserved and thawed in medium supplemented with 5 mM NAC shows the highest antioxidant and lowest ROS capability, good apoptotic parameters, and follicle viability. Our results need to be confirmed in larger patient cohorts prior to being accepted as a standard protocol.

摘要

目的：早发性卵巢功能不全在癌症患者放/化疗后经常发生。卵巢组织冻存与再移植在欧洲已成为临床常规, 最近已在中国第一个中心实施。我们研究了抗氧化剂N-乙酰半胱氨酸（NAC）在关键性冷冻-复苏步骤中的保护作用。

方法：13名癌症患者的卵巢组织取材后, 每位患者取15片卵巢组织样本前瞻性随机分配入一个对照组和四个不同NAC浓度的研究组（组1, 0mM NAC；组2, 0.5mM NAC；组3, 1mM NAC；组4, 5mM NAC；组5, 25mM NAC）。复苏后, 评估卵泡活性、DNA断裂水平、活性氧类物质（ROS）水平和总抗氧化能力（TAC）。

结果：采用25mM NAC（组5）冻存和复苏的卵巢组织基质细胞凋亡比例最少, 但卵泡活性最低。其余四组显示了相似的抗凋亡水平和良好的卵泡活性。组4中ROS水平最低而TAC水平最高。

结论：在冻存液和复苏液中添加5mM NAC显示了最高的抗氧化水平和最低的ROS水平, 良好的抗凋亡水平和卵泡活性。我们的结果在被接受为标准方案之前需要在较大样本量患者中得到证实。

Keywords:

• Ovarian tissue cryopreservation
• N-acetyl-l-cysteine
• follicle viability
• DNA fragmentation
• reactive oxygen species
• total antioxidant capability

Conflict of interest

The authors disclose no conflicts of interest. The authors alone are responsible for the content and writing of this paper.

Additional information

Funding

This study was supported by Beijing Municipal Administration of Hospitals Clinical medicine, Development of Special Funding Support [code: XMLX201710]; Capital’s Funds for Health Improvement and Research [code: 2016-2-2113]; Beijing Municipal Science & Technology Commission [code: Z161100000516143]; Beijing Municipal Administration of Hospitals’ Ascent Plan [code: DFL20181401]; Beijing Municipality Health Technology High-level Talent [code: 2014-2-016]; SAFEA: Project for Key Foreign Experts [code: 20181100005]; Beijing Nature Science Foundation [Y181004].