Figure 4

Transmission electron micrographs of vitrified-warmed canine germinal vesicle (GV) oocytes. A) Semi-thin section of a COC with a central nucleus (N). The cumulus cells densely compact around the oocyte. B) The cortical zone increases mitochondria (M) numerical density and decrease in cortical granule (CG) numerical density. C) Lipid vesicle turns into smaller droplets with broken membrane and replaced by mitochondria (asterisks). D) Smooth endoplasmic reticulum vesicles (SER) are scattered in pericortical cytoplasm. E) Mitochondria (M) are elongated and of decreased electron density. F) Showing broken CG (asterisk). C = cytoplasm, ZP = zona pellucida, N = nucleus, Cu = cumulus cells, CG = cortical granule, L = lipid droplet, SER = smooth endoplasmic reticulum vesicle.