Fine structure of Egyptian buffalo oocytes (Bubalus bubalis) during different in vitro maturation periods using transmission electron microscopy (TEM)

Abstract

This study was carried out to illustrate the ultrastructure of Egyptian buffalo oocytes through in vitro maturation (IVM) period (24 h). Selected cumulus oocytes complexes (COCs) were divided into three groups in relation to the time of maturation (8, 16 and 24 h >). After different maturation intervals, the matured oocytes were examined by light and transmission electron microscope (TEM). Results showed that the cumulus cells were close to each other and zona plucida (ZP) in the first group than the second and third group, lipid droplets (LD) appeared normal and nearly from plasma membrane in the group of oocytes matured in vitro for 8 h than oocytes matured in vitro for 24 h, microvilli (Mv) appeared with more number, higher thickness and penetrating the ZP and cytoplasm in the first group than other two groups, and mitochondria (M) in the first group were located near the plasma membrane, while in the third group it appeared as individual and scattered through the oocyte cell. Finally, the first polar body was observed in the third group only. This study showed the ultra-structural concepts of Egyptian buffalo oocytes during different IVM periods, and provided insights about the changes that occurred in oocytes during maturation process in the bovine species.

Keywords: Egyptian buffalo, oocytes, in vitro maturation (IVM), ultra structural