Fataneh Ghafari, Mazdak Salavati, Richard J Piercy, Ali A Fouladi-Nashta
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引用次数: 0
Abstract
In brief: Oxidative stress due to high-fat content damages canine oocytes during long period of in vitro maturation and compromises their developmental competence. This paper shows how melatonin protects the oocytes and increases development to metaphase II stage. Results from this study would be applicable to conservation of endangered and other animal species.
Abstract: Unlike other domesticated animals, in vitro maturation of canine oocytes results in poor nuclear maturation to the metaphase II stage and high oocyte degeneration. The high-fat content of canine oocytes is the likely cause; it predisposes them to oxidative stress and deleterious reactive oxygen species (ROS). Melatonin (MTN) (potentially acting as a powerful antioxidant) was reported to support in vitro cultured oocytes in other species. In this work, canine cumulus oocyte complexes (COCs) were collected after routine ovariohysterectomy. Immunocytochemistry for expression of melatonin receptors (MTNR-1A and 1B) revealed that both receptors were highly expressed in canine oocytes and there was lower expression in the cumulus cells. Canine COCs matured in vitro in melatonin-supplemented culture at 100 nM concentration in low (5%) O2 incubator had a lower percentage at GV stage (6.7% ± 4.2 vs 19.8% ± 3), a higher MII stage (32.3% ± 6.4 vs 15.81% ± 8.1), lower degeneration (20.5% ± 3.2 vs 45.2% ± 5.15) and higher meiotic resumption (GVBD-MII; 56.2% ± 8.6 vs 19% ± 3), and produced lower ROS (determined after DCHFDA staining) (all P < 0.005) than oocytes cultured in high O2 (20%) incubator. The expression of ROS-regulating genes GPX-1 and catalase was significantly reduced in oocytes cultured with melatonin in low O2 compared with high O2 (P < 0.05). Importantly, the oocyte maturation rate increased significantly when G-IVF PLUS, a commercial culture medium used in human oocyte culture, was supplemented with MTN (P < 0.05). These results support the main objective of this study to analyze the beneficial effects of melatonin and low oxygen tension on both health and the developmental competence of in vitro matured canine oocytes.
期刊介绍:
Reproduction is the official journal of the Society of Reproduction and Fertility (SRF). It was formed in 2001 when the Society merged its two journals, the Journal of Reproduction and Fertility and Reviews of Reproduction.
Reproduction publishes original research articles and topical reviews on the subject of reproductive and developmental biology, and reproductive medicine. The journal will consider publication of high-quality meta-analyses; these should be submitted to the research papers category. The journal considers studies in humans and all animal species, and will publish clinical studies if they advance our understanding of the underlying causes and/or mechanisms of disease.
Scientific excellence and broad interest to our readership are the most important criteria during the peer review process. The journal publishes articles that make a clear advance in the field, whether of mechanistic, descriptive or technical focus. Articles that substantiate new or controversial reports are welcomed if they are noteworthy and advance the field. Topics include, but are not limited to, reproductive immunology, reproductive toxicology, stem cells, environmental effects on reproductive potential and health (eg obesity), extracellular vesicles, fertility preservation and epigenetic effects on reproductive and developmental processes.