Němeček David, Chmelikova Eva, Petr Jaroslav, Kott Tomas, Sedmíková Markéta
Department of Veterinary Sciences, Czech University of Life Sciences, Prague, Czech Republic.
Institute of Animal Science, Uhřiněves, Czech Republic.
PeerJ. 2021 Mar 23;9:e10636. doi: 10.7717/peerj.10636. eCollection 2021.
Oxidative stress impairs the correct course of meiotic maturation, and it is known that the oocytes are exposed to increased oxidative stress during meiotic maturation in in vitro conditions. Thus, reduction of oxidative stress can lead to improved quality of cultured oocytes. The gasotransmitter carbon monoxide (CO) has a cytoprotective effect in somatic cells. The CO is produced in cells by the enzyme heme oxygenase (HO) and the heme oxygenase/carbon monoxide (HO/CO) pathway has been shown to have an antioxidant effect in somatic cells. It has not yet been investigated whether the CO has an antioxidant effect in oocytes as well. We assessed the level of expression of HO mRNA, using reverse transcription polymerase chain reaction. The HO protein localization was evaluated by the immunocytochemical method. The influence of CO or HO inhibition on meiotic maturation was evaluated in oocytes cultured in a culture medium containing CO donor (CORM-2 or CORM-A1) or HO inhibitor Zn-protoporphyrin IX (Zn-PP IX). Detection of reactive oxygen species (ROS) was performed using the oxidant-sensing probe 2',7'-dichlorodihydrofluorescein diacetate. We demonstrated the expression of mRNA and proteins of both HO isoforms in porcine oocytes during meiotic maturation. The inhibition of HO enzymes by Zn-PP IX did not affect meiotic maturation. CO delivered by CORM-2 or CORM-A1 donors led to a reduction in the level of ROS in the oocytes during meiotic maturation. However, exogenously delivered CO also inhibited meiotic maturation, especially at higher concentrations. In summary, the CO signaling molecule has antioxidant properties in porcine oocytes and may also be involved in the regulation of meiotic maturation.
氧化应激会损害减数分裂成熟的正常进程，并且已知在体外条件下，卵母细胞在减数分裂成熟过程中会受到增加的氧化应激影响。因此，降低氧化应激可提高培养卵母细胞的质量。气体递质一氧化碳（CO）在体细胞中具有细胞保护作用。CO由血红素加氧酶（HO）在细胞中产生，并且血红素加氧酶/一氧化碳（HO/CO）途径已被证明在体细胞中具有抗氧化作用。CO在卵母细胞中是否也具有抗氧化作用尚未得到研究。我们使用逆转录聚合酶链反应评估了HO mRNA的表达水平。通过免疫细胞化学方法评估HO蛋白的定位。在含有CO供体（CORM-2或CORM-A1）或HO抑制剂锌原卟啉IX（Zn-PP IX）的培养基中培养的卵母细胞中，评估了CO或HO抑制对减数分裂成熟的影响。使用氧化传感探针2',7'-二氯二氢荧光素二乙酸酯检测活性氧（ROS）。我们证明了在猪卵母细胞减数分裂成熟过程中两种HO同工型的mRNA和蛋白的表达。Zn-PP IX对HO酶的抑制不影响减数分裂成熟。CORM-2或CORM-A1供体提供的CO导致减数分裂成熟过程中卵母细胞中ROS水平降低。然而，外源性提供的CO也抑制减数分裂成熟，尤其是在较高浓度时。总之，CO信号分子在猪卵母细胞中具有抗氧化特性，并且可能也参与减数分裂成熟的调节。
