Niacin improves maturation and cryo-tolerance of bovine in vitro matured oocytes: An experimental study

Abstract

Background: Nicotinic acid (niacin) is a broad-spectrum lipid-modifying agent that has potent antioxidant properties and reduces the production of lipid peroxidation.
 Objective: The purpose of the present study was to investigate the maturation, embryo development and cryo-tolerance merit, and levels of malondialdehyde (MDA), total oxidant status, and total antioxidant capacity following the supplementation of bovine oocytes maturation medium with different concentrations of niacin.
 Materials and Methods: Immature cumulus-oocyte complexes were cultured in tissue culture medium-199 maturation media supplemented with 0, 100, 200, and 400 µM niacin under a standard in vitro culture condition. After 24 hr of culture, the nuclear maturation rate was assessed. Then, two groups of immature cumulus-oocyte complexes were cultured in TCM-199 either with or without 400 µM niacin and evaluated for embryo development. Also, matured cumulus-oocyte complexes in both groups were frozen using a standard vitrification procedure. After vitrification, oocytes were warmed in two steps and evaluated for embryo development. In addition, the level of total antioxidant capacity, total oxidant status, and MDA were measured.
 Results: The results indicated that although the treatment with 400µM niacin increased in vitro nuclear maturation (87.6 ± 5.3), it did not improved the embryo development to the blastocyst stage. Higher cleavage and blastocyst rates were observed in vitrified oocytes that were cultured with supplemented 400 µM niacin compared to the control group (without niacin) (53.6 ± 2.7 and 10.6 ± 1.6 vs. 46.2 ± 4.1 and 6.3 ± 2.4, respectively). Also, the addition of 400 µM niacin to the maturation media could decrease MDA levels after maturation.
 Conclusion: Niacin could improve the quality of in vitro embryo production (IVP) embryos and tolerance of bovine oocytes to vitrification.
 Key words: Bovine, Embryonic development, Niacin, Oocytes, Vitrification.

Supplementing media with NAD⁺ precursors enhances the <i>in vitro</i> maturation of porcine oocytes

“…Consistent with this, previous studies have also shown an improvement in oocyte quality when mouse follicles cultured in vitro were supplemented with NA [ 29 ]. Bovine oocytes treated with 400 µM NA also exhibited significant improvements in meiotic progression and developmental competence following vitrification [ 30 ], and blastocyst formation was significantly improved when porcine oocytes isolated from large antral follicles were supplemented with 600 µM niacin during IVM [ 31 ]. There was no effect on aged, in vitro matured murine oocytes at low doses of NA [ 18 ], however, a significant increase in intrinsic oocyte NAD + levels in the oocytes from aged mice compared with control mice was observed [ 18 ].…”

“…As such, supplementing the maturation media with NA in this study potentially provided the oocyte with a much greater capacity to produce NAD + than was possible from tryptophan alone. Together the findings suggest that the effective concentration of NA for improving oocyte quality differs between species and oocytes from follicles of different diameter [ 18 , 29 , 30 ].…”

Bovine oocyte developmental competence and gene expression following co-culturing with ampullary cells: An experimental study

“…The maturation medium included of TCM-199 supplemented with 0.1 IU/mL recombinant human FSH (Follitrope, LG Life Sciences, South Korea), 5 IU/mL highly purified hCG (Karma, Pharmatech GmbH, Germany), 50 μg/mL gentamicin, and 10% FCS. This experiment was carried out in five independent replicates (15).…”

“…On the day of evaluation, 1% aceto-orcein dye (1% orcein in 45% glacial acetic acid) was used to stain the COCc which were mounted on microscopic slides and examined in terms of nuclear morphology with a light microscope at × 100 and × 400 magnifications. Based on their nuclear status, the oocytes were categorized as mature, immature, metaphase І, and abnormal (any spindle and chromosomal abnormality) (15).…”

“…Following the IVM, the COCs were transferred to the fertilization medium (modified Tyrode's medium). In this study, previously tested frozen semen was used for fertilization (15). Motile spermatozoa (obtained through the swim -up method at a final concentration of 10 6 spermatozoa ml-1) and the oocytes were co-incubated for 18 hr at 38.5°C in 5% CO 2 by applying the highest relative humidity.…”