Instituto de Genética Veterinaria Prof. Fernando N. Dulout (IGEVET, UNLP-CONICET), Facultad de Ciencias Veterinarias (FCV), Universidad Nacional de La Plata (UNLP), Argentina.
Theriogenology. 2010 Oct 15;74(7):1141-8. doi: 10.1016/j.theriogenology.2010.05.015. Epub 2010 Aug 5.
The objective was to investigate the effects of supplementary zinc (Zn) during in vitro maturation (IVM) of bovine oocytes. The DNA damage in cumulus cells was low with supplemental Zn concentrations of 1.1 and 1.5 μg/mL in the IVM medium (mean ± SEM index of DNA damage was 67.52 ± 9.32, 68.52 ± 13.34, 33.80 ± 4.89, and 34.65 ± 7.92 for supplementation with 0, 0.7, 1.1, and 1.5 μg/mL Zn, respectively; P < 0.01). Total glutathione concentrations did not differ following Zn supplementation of 1.1 and 1.5 μg/mL (3.7 ± 0.4 vs. 4.0 ± 0.5 pmol, respectively, in oocytes; and in cumulus cells, 0.5 ± 0.04 nmol/10(6) cells, combined for both treatments), but were greater (P < 0.01) than supplementation with 0.7 μg/mL (1.8 ± 0.5 pmol in oocytes and 0.2 ± 0.02 nmol/10(6) cumulus cells). Cleavage rate increased (P < 0.05) when Zn was added to the IVM medium at any concentration (67.16 ± 1.17, 73.15 ± 1.15, 74.05 ± 1.23, and 72.76 ± 0.74 for 0, 0.7, 1.1, and 1.5 μg/mL Zn). For these concentrations, subsequent embryo development to the blastocyst stage was 17.83 ± 2.15, 21.95 ± 0.95, 27.65 ± 1.61, and 30.33 ± 2.78%, highest (P < 0.01) in oocytes matured with 1.5 μg/mL Zn. There was an increase (P < 0.05) in mean cell number per blastocyst obtained from oocytes matured with 1.1 and 1.5 μg/mL Zn relative to 0 Zn (IVM alone) and 0.7 μg/mL Zn. In conclusion, Zn during oocytes maturation significantly affected intracellular GSH content and DNA integrity of cumulus cells, and improved preimplantational embryo development. We inferred that optimal embryo development to the blastocyst stage was partially dependent on the presence of adequate Zn concentrations.
目的是研究在牛卵母细胞体外成熟（IVM）过程中补充锌（Zn）的影响。在 IVM 培养基中添加 1.1 和 1.5μg/ml 的 Zn 时，卵丘细胞的 DNA 损伤较低（平均±SEM 的 DNA 损伤指数分别为 67.52±9.32、68.52±13.34、33.80±4.89 和 34.65±7.92，分别补充 0、0.7、1.1 和 1.5μg/ml Zn；P<0.01）。在添加 1.1 和 1.5μg/ml Zn 后，总谷胱甘肽浓度没有差异（卵母细胞中分别为 3.7±0.4 和 4.0±0.5 pmol，卵丘细胞中为 0.5±0.04 nmol/10（6）细胞，两种处理均相同），但高于补充 0.7μg/ml Zn（卵母细胞中为 1.8±0.5 pmol，卵丘细胞中为 0.2±0.02 nmol/10（6）细胞）（P<0.01）。当在任何浓度下向 IVM 培养基中添加 Zn 时，卵母细胞的卵裂率均增加（P<0.05）（0、0.7、1.1 和 1.5μg/ml Zn 的卵裂率分别为 67.16±1.17、73.15±1.15、74.05±1.23 和 72.76±0.74）。对于这些浓度，随后胚胎发育至囊胚阶段的比例分别为 17.83±2.15、21.95±0.95、27.65±1.61 和 30.33±2.78%，其中添加 1.5μg/ml Zn 的卵母细胞成熟后最高（P<0.01）。与 0Zn（单独 IVM）和 0.7μg/ml Zn 相比，添加 1.1 和 1.5μg/ml Zn 的卵母细胞获得的每个囊胚的平均细胞数增加（P<0.05）。总之，Zn 在卵母细胞成熟过程中显著影响卵丘细胞内的 GSH 含量和 DNA 完整性，并提高了胚胎的植入前发育。我们推断，最佳的胚胎发育至囊胚阶段部分取决于存在足够的 Zn 浓度。
