Beneficial Effects of Melatonin on the In Vitro Maturation of Sheep Oocytes and Its Relation to Melatonin Receptors

Abstract

(1) Background: The binding sites of melatonin, as a multifunctional molecule, have been identified in human, porcine, and bovine samples. However, the binding sites and mechanisms of melatonin have not been reported in sheep; (2) Methods: Cumulus–oocyte complexes (COCs) were cultured in TCM-199 supplemented with melatonin at concentrations of 0, 10−3, 10−5, 10−7, 10−9, and 10−11 M. Melatonin receptors (MT1 and MT2) were evaluated via immunofluorescence and Western blot. The effects of melatonin on cumulus cell expansion, nuclear maturation, embryo development, and related gene (GDF9, DNMT1, PTX3, HAS2, and EGFR) expression were investigated. The level of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were evaluated in oocytes and cumulus, respectively; (3) Results: Both MT1 and MT2 were expressed in oocytes, cumulus cells, and granulosa cells. Melatonin with a concentration of 10−7 M significantly enhanced the rates of nuclear maturation, cumulus cells expansion, cleavage, and blastocyst. Melatonin enhanced the expression of BMP15 in oocytes and of PTX3, HAS2, and EGFR in cumulus cells. Melatonin decreased the cAMP level of oocytes but enhanced the cGMP level in oocytes and cumulus cells; (4) Conclusion: The higher presence of MT1 in GV cumulus cells and the beneficial effects of melatonin indicated that its roles in regulating sheep oocyte maturation may be mediated mainly by the MT1 receptor.

Effects of melatonin on the synthesis of estradiol and gene expression in pig granulosa cells

“…Studies using cell cultures and animals have revealed the beneficial effects of melatonin on oocyte maturation, development of growing follicles, embryonic development, and other reproduction activities in vitro and in vivo . Beneficial effects on the in vitro maturation of sheep oocytes and an increased ratio of vitrified sheep blastocysts have been demonstrated following melatonin application in vitro . Melatonin promotes oocyte maturation, and improves their subsequent fertilization rate in humans by reducing oxidative stress within oocytes .…”

Research progress on the role of melatonin and its receptors in animal reproduction: A comprehensive review

“…The melatonin works as an opposing oestrogen, hence enhancing immune system response (Sanchez‐Barcelo et al., ). It is a widely known fact that melatonin controls ovarian actions through the directive of gonadotrophin proclamation in the hypothalamus–pituitary gland axis through its particular receptors (Tan et al., ; Tian et al., ).…”

“…Melatonin and its metabolites act as dominant antioxidants, which can possibly prevent early ovarian miscarriage. From the current literature of background work (Arendt, ; Banach, Gurdziel, Jedrych, & Borowicz, ; De Leersnyder et al., ; Duffield et al., ; El‐Mokadem et al., ; Grossman, Laudon, & Zisapel, ; Henriquez et al., ; Hillier, ; Howard & Lutterschmidt, ; Hu, Christian, Sipes, & Hoyer, ; Jan et al., ; Kang et al., ; Koppisetti et al., ; Li et al., ; Maganhin et al., ; Mukherjee et al., ; Peres, Masruha, Zukerman, Moreira‐Filho, & Cavalheiro, ; Pierce & Parsons, ; Reiter et al., ; Reiter et al., ; Rozen, ; Saenz De Miera et al., ; Sambrook & Russell, ; Sanchez‐Barcelo et al., ; Singh & Haldar, ; Singh & Jadhav, ; Tian et al., ; Ubuka et al., ; Valenzuela, Vera, Venegas, Pino, & Lagunas, ; Vijayalaxmi, Reiter, Herman, & Meltz, , ; Weems, Goodman, & Lehman, ; Yoshimura, ; Yumnamcha et al., ), there has been extensive progress of action mechanism of melatonin and its related areas. For instance, the protection of gametes and embryos (Voiculescu et al., ), the response of clock genes (Saenz De Miera et al., ; Vriend & Reiter, ) and the immune‐neuroendocrine interactions (Vijayalaxmi et al., ) reconcile seasonal variations in immune functions and the silencing or blockage of genes.…”

“…The current investigation of this literature shows that melatonin performs a vigorous action in the pathogenesis of several reproductive practices. Melatonin consistently occurs in animals' pre-ovulation follicular fluid, and the melatonin receptors exist in ovarian GPs, which (Arendt, 1986;Banach, Gurdziel, Jedrych, & Borowicz, 2011;De Leersnyder et al, 2003;Duffield et al, 2002;El-Mokadem et al, 2017;Grossman, Laudon, & Zisapel, 2011;Henriquez et al, 2017;Hillier, 1994;Howard & Lutterschmidt, 2015;Hu, Christian, Sipes, & Hoyer, 2001;Jan et al, 2000;Kang et al, 2009;Koppisetti et al, 2008;Li et al, 2011;Maganhin et al, 2013;Mukherjee et al, 2015;Peres, Masruha, Zukerman, Moreira-Filho, & Cavalheiro, 2006;Pierce & Parsons, 1981;Reiter et al, 2010;Reiter et al, 2014;Rozen, 2003;Saenz De Miera et al, 2014;Sambrook & Russell, 2001;Sanchez-Barcelo et al, 2005;Singh & Haldar, 2007;Singh & Jadhav, 2014;Tian et al, 2017;Ubuka et al, 2012;Valenzuela, Vera, Venegas, Pino, & Lagunas, 2015;Vijayalaxmi, Reiter, Herman, & Meltz, 1996Weems, Goodman, & Lehman, 2015;Yoshimura, 2010;Yumnamcha et al, 2017), there has been extensive progress of action mechanism of melatonin and its related areas. For instance, the protection of gametes and embryos (Voiculescu et al, 2014), the response of clock genes…”

“…The melatonin works as an opposing oestrogen, hence enhancing immune system response (Sanchez-Barcelo et al, 2005). It is a widely known fact that melatonin controls ovarian actions through the directive of gonadotrophin proclamation in the hypothalamus-pituitary gland axis through its particular receptorsTian et al, 2017).Melatonin diminishes the intrafollicular oxidative mutilation and proliferation fertility proportions(Carnevali et al, 2011). Moreover, melatonin receptors have a reconciled function and also have the capability of detecting melatonin as an undeviating open drastic forager, which can significantly increase the understanding of melatonin's practices which in turn helps reproductive functioning.…”