Ameliorative Effects of Melatonin against Hydrogen Peroxide‐Induced Oxidative Stress on Boar Sperm Characteristics and Subsequent In Vitro Embryo Development

Abstract

Melatonin, the major secretory product of the pineal gland, scavenges a variety of reactive oxygen and nitrogen species in vivo and in vitro, indicating that melatonin is a potent function as an antioxidant. The objective of this study was to investigate the effect of melatonin in the presence or absence of hydrogen peroxide (H(2)O(2)) on sperm characteristics (motility, viability, survival rate, membrane integrity, lipid peroxidation (LPO) and mitochondria activity) and also to examine the developmental rates to the blastocysts stage of porcine oocytes fertilized in vitro with semen treated with or without melatonin (100 nM) in the presence or absence of H(2)O(2) (250 μM). The sperm were treated with melatonin in the presence or absence of H(2)O(2) for 3, 6, 9 and 12 h at 37°C and then analysed for the sperm characteristics. The porcine embryos were produced by in vitro maturation and in vitro fertilization (IVM/IVF) using semen treated with or without melatonin (100 nM) in the presence or absence of H(2)O(2) (250 μM) for 6 h. The semen characteristics, including motility, viability, survival rate, membrane integrity and mitochondria activity, were higher in the groups that were treated with melatonin in comparison to other groups, irrespective of incubation periods. Malondialdehyde levels in control, melatonin and melatonin + H(2)O(2) groups were lower than H(2)O(2) only group. A positive correlation was shown among motility, viability, survival rate and membrane integrity, but a negative correlation was observed between LPO and the other evaluation methods. The developmental rates to blastocysts of IVM/IVF porcine oocytes fertilized by semen treated with melatonin were significantly increased compared with any other groups, with the cell number of blastocysts shown to have a similar trend to the developmental rates. These results demonstrate that melatonin can improve the semen characteristics during in vitro storage and support the developmental ability of IVM/IVF embryos in pigs.

Evidence of melatonin synthesis in the ram reproductive tract

“…Therefore, the melatonin secreted by the testes can have the same function as that found in pre-ovulatory follicular fluid, which is to protect the spermatozoa from oxidative damage that could impair male fertility (Agarwal et al, 2008). Incubation of ejaculated spermatozoa with melatonin has resulted in decreased apoptotic-related changes in many species (Casao et al, 2010b;Dom ınguez-Rebolledo et al, 2010;Jang et al, 2010;Balao da Silva et al, 2011), including human (Du Plessis et al, 2010;Espino et al, 2011). Moreover, melatonin can not only act upon fully mature spermatozoa but also during spermatogenesis in the seminiferous tubules (Guneli et al, 2008;Ozen et al, 2008) and upon epidydimal spermatozoa (Huang et al, 2009;Sarabia et al, 2009), reducing oxidative damage, apoptosis, and DNA breakages.…”

The role of antioxidants in sperm freezing: a review

“…MLT has a key role in the regulation of the circadian wake-sleep cycle, immune enhancement, and also adjusting of seasonal reproduction (Reiter 1973). Moreover, it can stimulate the activity of antioxidant enzymes such as SOD and GSH-Px (Jang et al 2010). Interestingly, human seminal fluid contains melatonin and spermatozoa reportedly possess membrane receptor of melatonin (Ortiz et al 2011).…”

“…Trolox at the low millimolar range (0.1-1 mM) had a protective effect on thawed red deer spermatozoa by preventing rising of intracellular ROS and lipid peroxidation as well as by preventing DNA damage (Domínguez-Rebolledo et al 2009, 2010Martínez-Pastor et al 2008, 2009. Anel-López et al (2012) reported that Trolax is not a suitable extender supplement for the cryopreservation of epididymal deer spermatozoa, at least at the low millimolar range, since they found a decrease in motility and mitochondrial activity.…”

“…Interestingly, human seminal fluid contains melatonin and spermatozoa reportedly possess membrane receptor of melatonin (Ortiz et al 2011). MLT scavenges a variety of reactive oxygen and nitrogen species in vivo and in vitro, signifying it has a powerful non-enzymatic antioxidant property (Jang et al 2010). According to the findings of some studies, MLT improves semen characteristics not only in goat (Ramadan et al 2009), rat (Sönmez et al 2007), boar (Jang et al 2010 In addition, MLT implantation to sperm donor rams enhanced the ability of sperm cells to undergo cryopreservation, bringing about improved viability and intact acrosome rates in post-thaw samples and decreased enzyme leakage through sperm cells during cryopreservation (Kaya et al 2001).…”

Pineal Gland Plays a Role in Gonadal Development after Eyelids Separation in Puppies

“…In addition, melatonin implantation into male animals significantly elevated serum testosterone levels which subsequently increased sperm number, motility and the fertilization rate (Casao et al, 2010). Furthermore, eggs fertilized by melatonin-treated sperms have significantly higher developmental rates to the blastocyst stage (Jang et al, 2010). Considering these findings, it is now thought that melatonin is not always antigonadotropic.…”