Evaluation of mouse oocyte mitochondrial distribution in different developmental stages using confocal microscopy

Mitochondria is a critical organelle within the cell and has important role in the oocyte development, thus the aim of this study was the comparison of mitochondrial distribution within the mouse oocyte at germinal vesicle (GV), germinal vesicle breakdown (GVBD) and metaphase II (MII) stages using laser confocal microscopy (LSCM). After superovulation of adult mouse (FVB/N) using 7.5 IU PMSG the oocytes at GV, GVBD and MII were collected mechanically from the ovary then they were stained with (1 microgram per 1 ml) 5,5´6,6´-tetrachloro-1,1,3,3´tetraethylbenz-imidazolycarbocyanine iodide or JC-1 for ten min at 37ºC. Then they were observed under LSCM at 515-530 nm wavelengths for green light. Our observation showed the mitochondria were distributed homogenously within the cytoplasm of GVBD and MII oocytes as green staining but they were heterogeneously within the GV oocytes and some of them were located around the oocyte nucleus as a ring. Our results showed two mitochondrial distribution patterns within the mouse oocytes at different developmental stages. It seems that the main factors for distribution of mitochondria within the cells is their need for producing ATP and usage of the energy.