T he duration of follicles' formation from primordial follicle stage to ovulation is differed among species (Hunter et al., 2004; van den Hurk and Santos, 2009). Follicular wave emergence is preceded by an increase offollicle stimulating hormone (Baby and Bartlewski, 2011). Granulosa cells around the time of follicular selection acquire LHreceptors that are essential for further development (Webb et al., 2003; Baird and Mitchell, 2013). Mature ovulatory follicles are characterized with high expression of aromatase in the granulosa cells, high concentration of estradiol hormone in follicular fluid and acquisition of LH receptors on granulosa cells (Shores and Hunter, 2003; Webb et al., 2003). Follicular diameter and follicular fluid composition are affected by follicular development and/or level of nutrition during estrous cycle (Mohammed 2011, Mohammed and Attaai 2011, Mohammed et al., 2012, Mohammed and Kassab 2015). This in turn affects oocyte maturation and subsequent embryo development. Some components are changed by follicular growth and development and/or by level of nutrition and are known to influence oocyte maturation and/or embryo development. Therefore, inclusion of follicular component(s) (
Background: The beneficial effects of myo-inositol to mammals on physiological and reproductive functions and treatments of malfunctions have been reported. The aims of present study were to assess the efficacy of myo-inositol supplementation on physiological and reproductive performances through blood parameters, oocyte quality and embryo transfer in mice. Methods: Seventy-five virgin female mice were classified into three equal groups; control group (T1) versus two myo-inositol groups (T2 receive 30 mmol/l and T3 receive 60 mmol/l). Changes of body temperature, blood oxygen and glucose, heart rate, blood parameters (RBCs, WBCs, hematocrit, glucose and total protein), oocyte quality (cumulus enclosed, diameter and brilliant cresyl blue stain) and reproductive performances (litter weight and size) were determined. Result: The results indicated that myo-inositol supplementation resulted in significant increase in values of RBCs, WBCs, hematocrit and total protein in addition to significant hypoglycemia. The quality of oocytes in case of cumulus enclosed, diameter and brilliant cresyl blue staining and reproductive performances were improved due to myo-inositol supplementation. Furthermore, myo-inositol supplementation effectively alleviated hypothermia and hyperglycemia following general anaesthesia.
Oocytes are bathed in extracellular fluid of the antral follicles, which is termed follicular fluid (FF). Follicular fluid is synthesized from secretions of theca, granulosa, and cumulus cells and from a transudate of blood plasma. Oocytes persist in meiotic arrest in antral follicles until luteinizing hormone (LH) surge or removal the oocytes from the ovarian follicles. This suggests that FF before LH surge might contain meiosis inhibiting factor(s). The microvasculatory bed of the follicular wall and the composition of FF undergo changes during follicular growth and development, which is important for oocyte maturation and subsequent embryo development. Therefore, it is expected that FF composition and components might change according to timing of FF aspiration from follicles. Hence, negative or positive effects could be expected when FF supplemented during oocyte maturation in vitro. Nutrition effects on microvasculatory bed of follicles and their sizes. Thus, the nutritional status of animals is a factor affected on oocyte maturation and embryo development. The present article reviews and discusses these effects.
Vitrification is an economically effective method for embryo cryopreservation in human and livestock animals; however, it carries the risk of damage by the exposure to severe oxidative stress. The present study was conducted to evaluate the effect of leptin at different levels on the in vitro development of fresh and vitrified preimplantation embryos in a rabbit model. Normal embryos at morulae stage were randomly cultured for 2 h with 0, 10, 20 or 100 ng/mL of leptin, then were cultured for further 48 h as freshly or after vitrification. Thereafter, developed blastocysts form the best leptin level in fresh and vitrified embryos along with their controls were allocated to analyze the pro-oxidant (malondialdehyde, MDA; nitric oxide, NO), antioxidant (total antioxidant capacity, TAC; superoxide dismutase, SOD; glutathione peroxidase, GPx), apoptotic (Bcl-2 associated X protein, BAX; heat shock 60kD protein member 1, HSP60; tumor necrosis factor alpha, TNFα) and developmental (sex determining region Y box protein 2, SOX2; Nanog homeobox protein, NANOG; Octamer-binding protein 4, OCT4) biomarkers. Results indicate that expanding and hatching rates of embryos were significantly higher at 20 ng/mL leptin than the other levels, while vitrification had an independent suppression effect on the in vitro development rates. The MDA and NO were significantly higher, while TAC, SOD and GPx were significantly lower in the vitrified than fresh embryos. In contrast, leptin treatment significantly decreased the pro-oxidant biomarkers and increased the antioxidant biomarkers in both fresh and vitrified embryos. Vitrification significantly increased the antiapoptotic biomarkers, and decreased the developmental biomarkers in embryos. In contrast, leptin decreased the BAX and TNFα, increased the HSP60, and moreover, ameliorated the reduction of developmental biomarkers in the vitrified embryos. These results conclude that leptin could be used as antiapoptotic and antioxidant promotor to support the in vitro embryonic development, particularly under oxidative stress emerged from cryopreservation programs.
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