The Role Of AIFM2 During Mouse Oocyte Maturation And Pre-implantation Embryo Development

Mammalian oocyte meiotic maturation and preimplantation embryonic development are complex and dynamic biological processes regulated by transcription factors.These transcriptional regulators are critical for the developmental potential of eggs and preimplantation embryos.Studies have found that mitochondrial apoptosisinducing factor 2(AIFM2)plays an important role in the regulation of mitochondrial function,apoptosis and lipid peroxidation.However,the role of AIFM2 in mouse oocyte meiotic maturation and preimplantation embryo development remains unknown.The main work and results of this study are as follows:(1)The role of AIFM2 in the maturation of mouse oocytesThe results of immunofluorescence and Western blotting analysis showed that AIFM2 was expressed in both GV stage and MII stage oocytes.By using AIFM2 highly selective inhibitor i FSP1 to inhibit AIFM2 activity,the effect of AIFM2 activity on meiotic maturation of mouse oocytes was analyzed.The results showed that inhibition of AIFM2 activity significantly reduced the occurrence of GVBD(p<0.05)and the excretion rate of the first polar body(p<0.05)in mouse oocytes.In this study,the indicators related to oxidative stress in mouse oocytes were detected.The results showed that the level of ROS in mouse oocytes was significantly increased(p<0.01)and the level of SOD was significantly decreased(p<0.01)after the activity of AIFM2 was inhibited.Further study found that the mitochondrial membrane potential level(p<0.05)and ATP content of oocytes were significantly reduced(p<0.01),resulting in mitochondrial dysfunction.(2)The role of AIFM2 in the development of mouse preimplantation embryosThe results of immunofluorescence and Western blotting showed that during the development of mouse preimplantation embryos,the relative expression of AIFM2 showed an increasing expression pattern with the increase of cells.Inhibition of AIFM2 activity significantly reduced the rate of mouse preimplantation embryo development to blastocyst stage(p<0.01).Moreover,inhibition of AIFM2 activity resulted in a significant decrease in blastocyst diameter(p<0.01),blastocyst cell number(p<0.05),and blastocyst cell ratio(p<0.01).Further research found that the level of intracellular ROS at the 2-cell stage of preimplantation embryos in mice was significantly increased after the activity of AIFM2 was inhibited(p<0.01).The SOD level was significantly decreased(p<0.05),the mitochondrial membrane potential level(p<0.01)and the ATP content were significantly decreased(p<0.05).TUNEL results showed that the apoptosis ratio of preimplantation embryos at the blastocyst stage of mice was significantly increased after AIFM2 activity was inhibited(p<0.01).RT-PCR results showed that after the activity of AIFM2 was inhibited,Nanog and Pou5f1 m RNA levels were significantly decreased at the blastocyst stage of mouse preimplantation embryos,and Caspase-3 m RNA levels were significantly increased at the blastocyst stage of mouse preimplantation embryos.In conclusion,this paper investigated the role of AIFM2 in mouse oocyte maturation and preimplantation embryo development.It is proved that inhibition of AIFM2 activity can cause oxidative stress and mitochondrial dysfunction in mouse oocytes and preimplantation embryos,thereby inhibiting their developmental potential.The results can provide a theoretical basis for revealing important events and regulatory mechanisms during the meiotic maturation of mouse oocytes and preimplantation embryonic development.