عنوان مقاله [English]
Introduction Oocyte maturity includes nuclear and cytoplasmic maturity, both of which are important for embryo fertilization. Cytoplasmic maturation involves the redistribution of a range of organelles, including mitochondria. The nuclear and cytoplasmic mammalian oocytes maturation is a complex process nuclear maturation is demonstrated by extrusion of first polar body while there may be no indication for cytoplasmic maturation According to critical role of mitochondria for energy production in oocytes, it can be considered as an indicator of cytoplasmic maturation. Oocyte maturation requires more energy. Energy reaches its peak during ovulation. Changes in the mitochondrial distribution pattern can affect the ability of embryo development from oocytes. Since fetal mitochondrial replication is not performed until the blastocyst its stage, mature Oocytes (MII), fertilized Oocytes, Energy required for fertilization, embryonic development prior to implantation and early stages of fetal development depend on the storage of mitochondria in the time of ovulation. Therefore, the location and function of mitochondria can affect the quality of the Oocyte and consequently interfere with the process of embryo development. The topic of genetic networks explores the most important genes in a physiological process. The graph theory is used to construct and reconstruct the biology network. In biology networks, genes, proteins, or any other molecule that plays a role in a cell can be considered as a node and the relationship between these nodes is considered as an edge.
Materials and Methods In this study, GEO access codes for this data set GSE38345 were used to determine the effect of FSH on the expression of mitochondrial genes. In the past decade, with the ability to study genetic information of the genome in a wide range, micro arrays were a high-performance method for analyzing gene expression. The data are microarray and contain the gene expression information for cow's oocyte cells, whose maturity is influenced by the FSH hormone under laboratory conditions. After data implementation, the quality of the data was analyzed and if necessary, normalization was performed using the data conversion technique. Data analysis and comparison of gene expression in two cases before maturation (20 hours after oocyte treatment with FSH in laboratory conditions) and after maturation (96 hours after oocyte treatment with FSH in laboratory conditions) using From the GEO2R software link were done. After identifying the genes and examining the different genes expressed, two genotypes included Increased and decreased expression genes. The interaction of each gene group was studied using a string database based on co-expression data. Gene ontology was performed using the comparative GO database.
Results and Discussion In a comparison between oocyte gene expression data in the pre-maturation stage and the post-maturation stage after treatment with FSH, it was determined that 100 mitochondrial genes in maturation compared to pre-maturation stage increased expression and 94 genes of this organ has declined. Among them, the protein interaction network has been identified in a set of increased and decreased expression genes. Of the 100 genes that have been increased expression, 68 genes are coexpression based on string information. Among decreased expression genes, 53 genes from 64 genes were reported as coexpression. In the protein interaction network of the increased expression genes, the important genes of MRPS10, MRPS18A, MRPL16 and MRPL17, which played a role in the mitochondrial destruction and translation processes of mitochondrial genes, and in the network of decreased expression genes, MRPL22, ATP5B and ATP5C1 genes, which by reducing its expression, attempted to balance in the pathways associated with mitochondrial destruction and ATP production through its role in the ATP synthase structure.
Conclusion The results of this study reveal the most important genes affecting mitochondrial activity during oocyte maturation and control genes of this organ according to the network of protein interactions in the set of increased and decreased expression genes. In addition, the most important biological pathways in order to understand the mechanism of FSH effect on oocyte maturation through mitochondrial organ is investigated. Also, by comprehensive examining the gene expression network in the process of cytoplasmic oocyte maturation and showing the marker genes and different biochemical pathways, it is possible to understand the quality of oocyte during maturation, which can help improve IVM-IVF technique. Since effective mechanisms in cytoplasmic maturity are not yet fully understood, efforts to identify important regulators of mitochondria in oocyte maturation process will be effective in using fertility technology in animal production.