Effect of granulosa cell co-culture in different embryonic stages on the development of in vitro-produced bovine embryos

Abstract

Success of in vitro maturation of mammalian oocytes and subsequently embryo production are normally affected by several factors such as hormonal alterations and culture conditions including nutrients or natural extracts. The leaves of Moringa oleifera are a good source for both macro- and micronutrients, and rich source of β-carotene, protein, vitamin C, calcium, and potassium. Gene expression techniques have become a powerful tool to analyze the relative abundance of transcripts related to quality of oocytes. In the present study, the relationship between mRNA expression profiles of maturation related genes [Cyclin B, cell division control (CDC2, CD44), extracellular signal-regulated kinases (ERK2) and c-mos genes], progression of meiosis and calcium concentration of sheep oocytes was evaluated. To carry out this study cumulus–oocyte complexes (COCs) aspirated from sheep ovaries were used. COCs were allocated in several groups cultured in TCM-199 medium without or with hormones plus different concentration of M. oleifera extract (20, 50 and 100 μg/ml). The results indicated that the relative abundance of the maturation related genes was affected by the concentration of M. oleifera extract and meiotic progression. Moreover, sheep oocytes cultured with hormones plus M. oleifera extract expressed high levels of the [Ca2+] concentration. The results suggest that M. oleifera combined with hormone supplementations improved the rate of maturation of sheep oocytes and could have acted as a promoter to induce mRNA expression and synthesis of essential protein, e.g. MPF, for the maturational processes.