Dehghani Naeimeh, Dianatpour Mehdi, Hosseini Seyed Ebrahim, Khodabandeh Zahra, Daneshpazhouh Hamed
Department of Biology, College of Science, Fars Science and Research Branch, Islamic Azad University, Fars, Iran.
Department of Biology, College of Science, Shiraz Branch, Islamic Azad University, Shiraz, Iran.
Iran J Med Sci. 2019 Sep;44(5):406-414. doi: 10.30476/IJMS.2019.44960.
Gamete cryopreservation is an inseparable part of assisted reproductive technology, and vitrification is an effective approach to the cryopreservation of oocytes. The aim of this study was to investigate vitrification effects on the expression levels of mitochondrial transcription factor A (Tfam) and mitochondrial-encoded cytochrome c oxidase subunit 1 (Cox1) in mouse metaphase II oocytes.
Oocytes were selected by simple random sampling and distributed amongst five experimental groups (control [n=126], docetaxel [n=132], docetaxel+cryoprotectant agent [CPA] [n=134], docetaxel+vitrification [n=132], and vitrification [n=123]). After the warming process, the oocytes were fertilized and cultured into a 2-cell stage. Then, the effects of vitrification on the expression of the Tfam and Cox1 genes were determined via real-time reverse transcriptase polymerase chain reaction. Each group was compared with the control group. The data were analyzed with ANOVA using GraphPad and SPSS, version 21.
A significant decrease was observed in the fertilization rate of each group in comparison with the control group (P=0.001). The rate of 2-cell formation after in vitro fertilization was significantly lower in both vitrification groups (docetaxel+vitrification and vitrification) than in the non-vitrification groups (fresh control and docetaxel) and control group (P=0.001 and P=0.004). The expression level of Cox1 was significantly higher in the vitrification group than in the control group (P=0.01), while it was lower in the docetaxel group than that in the control group (P=0.04). The expression level of the Tfam gene was significantly high in the vitrification group (vitrification+docetaxel) and the non-vitrified group (docetaxel+CPA) in comparison with the control group (P=0.01).
This study indicated that the vitrification of mouse MII oocytes increased the expression of the Tfam and Cox1 genes.
配子冷冻保存是辅助生殖技术中不可或缺的一部分，而玻璃化是卵母细胞冷冻保存的一种有效方法。本研究的目的是探讨玻璃化对小鼠减数分裂II期卵母细胞中线粒体转录因子A（Tfam）和线粒体编码的细胞色素c氧化酶亚基1（Cox1）表达水平的影响。
通过简单随机抽样选择卵母细胞，并将其分配到五个实验组（对照组[n = 126]、多西他赛组[n = 132]、多西他赛+冷冻保护剂[CPA]组[n = 134]、多西他赛+玻璃化组[n = 132]和玻璃化组[n = 123]）。解冻后，使卵母细胞受精并培养至2细胞期。然后，通过实时逆转录聚合酶链反应测定玻璃化对Tfam和Cox1基因表达的影响。将每组与对照组进行比较。使用GraphPad和SPSS 21版软件通过方差分析对数据进行分析。
与对照组相比，每组的受精率均显著降低（P = 0.001）。两个玻璃化组（多西他赛+玻璃化组和玻璃化组）体外受精后的2细胞形成率均显著低于非玻璃化组（新鲜对照组和多西他赛组）和对照组（P = 0.001和P = 0.004）。玻璃化组中Cox1的表达水平显著高于对照组（P = 0.01），而多西他赛组中的表达水平低于对照组（P = 0.04）。与对照组相比，玻璃化组（玻璃化+多西他赛）和非玻璃化组（多西他赛+CPA）中Tfam基因的表达水平显著升高（P = 0.01）。
本研究表明，小鼠MII期卵母细胞的玻璃化增加了Tfam和Cox1基因的表达。
