Effects on in vitro embryo development and intracellular glutathione content of the presence of thiol compounds during maturation of prepubertal goat oocytes

Abstract

The low number of embryos produced from in vitro matured, fertilized, and cultured (IVM-IVF-IVC) oocytes of prepubertal goat is mainly due to a low incidence of sperm head decondensation at fertilization (Martino et al., 1995: Theriogenology 43:473-485; Mogas et al., 1997: Theriogenology 48:815-829). Thiol compounds stimulate glutathione (GSH) synthesis and improve the rates of male pronucleus (MPN) formation and embryo development. The present study was carried out to determine whether supplementation of the IVM medium with 100 microM of cysteamine, 100 microM of beta-mercaptoethanol, 0.57 mM of cysteine, and 0.57 mM cystine might improve the embryo development and intracellular GSH level of prepubertal goat oocytes. After 27 hr post IVM, a sample of oocytes was frozen and the intracytoplasmic GSH content was evaluated by spectrophotometry. IVM-oocytes were inseminated with fresh semen and cultured in SOF medium. Only the addition of cysteamine to IVM media significantly improved the percentage of the morula plus blastocyst yield compared to the control group (oocytes matured in absence of thiol compounds) (22.2 vs. 6.4%, respectively; P < 0.05). The percentage of expanded blastocysts in cysteamine and control groups was 13.0 and 2.6%, respectively, and the mean cell number per blastocyst was 86.8 and 60.5, respectively. None of the other thiol compounds studied significantly improved the percentage of embryos obtained. It has been demonstrated that prepubertal goat oocytes synthesize GSH during IVM and that thiol compounds increase this GSH synthesis. In conclusion, only the addition of 100 microM of cysteamine to the maturation medium improves embryo development from prepubertal goat oocytes although all the thiol compounds used in this study increased intracellular GSH content.

Using cysteine/cystine to overcome oxidative stress in goat oocytes and embryos cultured in vitro

“…Thus, the GSH content of oocytes protects the zygote and early embryos from oxidative damage prior to genomic activation (7). The addition of cysteine to oocyte culture media has been shown to increase intracellular levels of GSH in buffaloes (8,9), pigs (10) and goats (11). However, the effects of supplementation with a specific concentration of cysteine depend on the dose, the species and the maturation medium (2).…”

The interactions between cysteamine, cystine and cumulus cells increase the intracellular glutathione level and developmental capacity of goat cumulus-denuded oocytes

“…In somatic cells, cysteamine can reduce cystine to cysteine, promoting cysteine uptake and hence enhancing GSH synthesis (Issels et al 1988). The addition of cysteamine to the culture medium improved oocyte maturation and development by increasing the GSH content of COCs (de Matos et al 1995, Abeydeera et al 1998, Gasparrini et al 2000, Rodriguez et al 2003, Kobayashi et al 2006. However, whether the cystine contained in TCM-199 (83.2 mM) is sufficient for oocyte IVM of different species is unknown.…”

“…However, whether the cystine contained in TCM-199 (83.2 mM) is sufficient for oocyte IVM of different species is unknown. While enrichment of maturation medium with cystine increased both GSH contents and embryonic development in the cow (de Matos et al 1997, de Matos & Furnus 2000 and buffalo (Gasparrini et al 2006), it increased only GSH synthesis of goat oocytes (Rodriguez et al 2003).…”

Microtubule assembly andin vitrodevelopment of bovine oocytes with increased intracellular glutathione level prior to vitrification andin vitrofertilization

“…However, the GSH levels of oocytes matured under in vitro conditions are lower when compared with those of ovulated 65 oocytes, as reported in some species (Ge et al, 2008;Brad et al, 2003;Rodríguez-González et al, 2003;Kim et al, 2007). The GSH synthesis of oocytes during in vitro maturation (IVM) may be disturbed by a low availability of cysteine (Meister, 1983;Furnus & de Matos, 1999).…”