Influence of manganese on apoptosis and glutathione content of cumulus cells during in vitro maturation in bovine oocytes

Abstract

We have investigated the effect of different Mn concentrations on (1) DNA integrity of cumulus cells by olive tail moment (OTM); (2) cumulus cells apoptosis by Annexin V staining assay; (3) intracellular total glutathione (GSH-GSSG) content; and (4) oocyte nuclear maturation and embryo cleavage after in vitro fertilisation (IVF). For this purpose, 0 (control), 2 (Mn1), 5 (Mn2) and 6 ng/mL (Mn3) Mn concentrations were added to IVM medium. Comet assay analysed by OTM was significantly higher in cumulus cells arising from COCs matured without Mn (control, P < 0.01) respect to cumulus cells obtained from COCs matured with Mn (control: 5.18 ± 2.3; Mn1: 2.93 ± 2.2; Mn2: 2.63 ± 2.4; Mn3: 2.92 ± 2.4). The frequency of apoptotic cells was higher in the control group (control: 6.63 ± 0.59; Mn1: 5.05 ± 0.5; Mn2: 4.61 ± 0.49; Mn3: 3.33 ± 0.42). Intracellular concentration of GSH-GSSG increased in oocytes and cumulus cells matured in the presence of Mn (P < 0.01). There were no differences in percentages of nuclear maturation when Mn was added to IVM medium at any concentration, but at 6 ng/mL Mn a higher cleavage rate was observed respect to the control group (P < 0.05). In conclusion, deficiency in Mn concentration during in vitro maturation increased the damage in the DNA molecule and the frequency of apoptotic cumulus cells. However, the addition of an adequate Mn concentration (6 ng/mL Mn) to IVM medium improved the health of cumulus-oocyte complexes and produced more cleaved embryos 48 h after IVF.

Effect of eicosapentaenoic acid on bovine cumulus–oocyte complex in vitro

“…Genotoxicity and cytotoxicity studies have been conducted to test numerous compounds using several end points on different test systems (Anchordoquy et al, 2014;Nikoloff et al, 2016;Ruiz de Arcaute et al, 2016). Numerous works have shown that the use of CC and oocyte in vitro for genotoxic and cytotoxic evaluation is a valuable and good tool for the rapid and sensitive detection of effect induced by various compound (Anguita et al, 2007;Chung et al, 2007).…”

Effects of manganese on maturation of porcine oocytes <i>in vitro</i> and their subsequent embryo development after parthenogenetic activation and somatic cell nuclear transfer

“…Moreover, the DNA integrity can be preserved and developmental competence of bovine oocytes to blastocyst stage can be increased through the antioxidant effect of Mn in cumulus oocyte complexes (COCs) [28]. Furthermore, the addition of Mn to maturation medium not only improved the competence of oocytes to be fertilized but also decreased the frequency of apoptotic cumulus cells [29]. Mn functions as a cofactor for several important enzymes such as arginase, pyruvate decarboxylase, and glutamine synthase [30], which are involved in DNA synthesis [31] and DNA protection [25].…”

The importance of manganese in the cytoplasmic maturation of cattle oocytes: blastocyst production improvement regardless of cumulus cells presence duringin vitromaturation

“…However, bovine Mn status were defined by Kincaid (1999) as deficient when Mn plasma concentration is lower than 6 ng/ml, and adequate when are between 6–70 ng/ml. Our studies have demonstrated that Mn concentrations in bovine are similar in plasma and follicular fluid (Anchordoquy et al , 2013, 2014). Adequate Mn concentration ‘protects’ cumulus cells from apoptosis (Anchordoquy et al , 2014).…”