Schwarz K R L, Pires P R L, de Bem T H C, Adona P R, Leal C L V
Departamento de Ciências Básicas, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga-SP, Brazil.
Reprod Domest Anim. 2010 Feb;45(1):75-80. doi: 10.1111/j.1439-0531.2008.01242.x.
The importance of nitric oxide synthase (NOS) in bovine oocyte maturation was investigated. Oocytes were in vitro matured with the NOS inhibitor N(w)-L-nitro-arginine methyl-ester (10(-7), 10(-5) and 10(-3) m L-NAME) and metaphase II (MII) rates and embryo development and quality were assessed. The effect of L-NAME (10(-7) m) during pre-maturation and/or maturation on embryo development and quality was also assessed. L-NAME decreased MII rates (78-82%, p < 0.05) when compared with controls without L-NAME (96%). Cleavage (77-88%, p > 0.05), Day 7 blastocyst rates (34-42%, p > 0.05) and total cell numbers in blastocysts were similar for all groups (146-171 cells, p > 0.05). Day 8 blastocyst TUNEL positive cells (3-4 cells) increased with L-NAME treatment (p < 0.05). For oocytes cultured with L-NAME during pre-maturation and/or maturation, Day 8 blastocyst development (26-34%) and Day 9 hatching rates (15-22%) were similar (p > 0.05) to controls pre-matured and matured without NOS inhibition (33 and 18%, respectively), while total cell numbers (Day 9 hatched blastocysts) increased (264-324 cells, p < 0.05) when compared with the controls (191 cells). TUNEL positive cells increased when NOS was inhibited only during the maturation period (8 cells, p < 0.05) when compared with the other groups (3-4 cells). NO may be involved in meiosis progression to MII and its deficiency during maturation increases apoptosis in embryos produced in vitro. Nitric oxide synthase inhibition during pre-maturation and/or maturation affects embryo quality.
研究了一氧化氮合酶（NOS）在牛卵母细胞成熟过程中的重要性。用NOS抑制剂N（ω）-L-硝基精氨酸甲酯（10⁻⁷、10⁻⁵和10⁻³ mol/L的L-NAME）对卵母细胞进行体外成熟培养，并评估中期II（MII）率、胚胎发育情况和质量。还评估了在成熟前和/或成熟过程中L-NAME（10⁻⁷ mol/L）对胚胎发育和质量的影响。与未添加L-NAME的对照组（96%）相比，L-NAME降低了MII率（78 - 82%，p < 0.05）。所有组的卵裂率（77 - 88%，p > 0.05）、第7天囊胚率（34 - 42%，p > 0.05）以及囊胚中的总细胞数相似（146 - 171个细胞，p > 0.05）。L-NAME处理使第8天囊胚TUNEL阳性细胞（3 - 4个细胞）增加（p < 0.05）。对于在成熟前和/或成熟过程中用L-NAME培养的卵母细胞，第8天囊胚发育率（26 - 34%）和第9天孵化率（15 - 22%）与未进行NOS抑制的成熟前和成熟对照组（分别为33%和18%）相似（p > 0.05），而与对照组（191个细胞）相比，总细胞数（第9天孵化的囊胚）增加（264 - 324个细胞，p < 0.05）。与其他组（3 - 4个细胞）相比，仅在成熟期间抑制NOS时TUNEL阳性细胞增加（8个细胞，p < 0.05）。NO可能参与减数分裂向MII的进程，其在成熟过程中的缺乏会增加体外产生的胚胎中的细胞凋亡。成熟前和/或成熟过程中抑制一氧化氮合酶会影响胚胎质量。
