Meuter Alexandra, Rogmann Lisa-Marlen, Winterhoff Boris J, Tchkonia Tamar, Kirkland James L, Morbeck Dean E
Division of Reproductive Endocrinology and Infertility, Mayo Clinic, 200St SW, Rochester, MN, 55905, USA.
J Assist Reprod Genet. 2014 Oct;31(10):1259-67. doi: 10.1007/s10815-014-0299-8. Epub 2014 Aug 10.
We aimed to determine whether embryo culture induces markers of cellular senescence and whether these effects were dependent on culture conditions.
Murine blastocysts were derived in vitro and in vivo and assessed for 2 primary markers of senescence: senescence-associated β-galactosidase (SA-β-gal) and phosphorylated H2A.X (γ-H2A.X), the latter being a mark of DNA oxidative damage. Expression of senescence-associated genes p21, p16, and interleukin 6 (IL6) were also assessed.
Compared with in vivo-derived blastocysts, in vitro embryos had high levels of SA-β-gal, nuclear γ-H2A.X, and p21 mRNA expression, indicating that a senescence-like phenotype is induced by in vitro culture. To determine the role of culture conditions, we studied the effect of oxygen (5 % vs 20 %) and protein supplementation on senescence markers. Blastocysts in reduced oxygen (5 %) had low levels of both SA-β-gal and γ-H2A.X compared with blastocysts cultured in ambient oxygen. Senescence markers also were reduced in the presence of protein, suggesting that antioxidant properties of protein reduce oxidative DNA damage in vitro.
Elevated SA-β-gal, γ-H2A.X, and p21 suggest that in vitro stress can induce a senescence-like phenotype. Reduced oxygen during embryo culture minimizes these effects, providing further evidence for potential adverse effects of culturing embryos at ambient oxygen concentrations.
我们旨在确定胚胎培养是否会诱导细胞衰老标志物，以及这些影响是否取决于培养条件。
体外和体内获得小鼠囊胚，并评估衰老的2种主要标志物：衰老相关β-半乳糖苷酶（SA-β-gal）和磷酸化H2A.X（γ-H2A.X），后者是DNA氧化损伤的标志物。还评估了衰老相关基因p21、p16和白细胞介素6（IL6）的表达。
与体内来源的囊胚相比，体外培养的胚胎具有高水平的SA-β-gal、核γ-H2A.X和p21 mRNA表达，表明体外培养诱导了类似衰老的表型。为了确定培养条件的作用，我们研究了氧气（5%对20%）和蛋白质补充对衰老标志物的影响。与在环境氧气中培养的囊胚相比，低氧（5%）条件下的囊胚SA-β-gal和γ-H2A.X水平均较低。蛋白质存在时衰老标志物也减少，这表明蛋白质的抗氧化特性可减少体外DNA氧化损伤。
SA-β-gal、γ-H2A.X和p21升高表明体外应激可诱导类似衰老的表型。胚胎培养期间降低氧气浓度可将这些影响降至最低，这为在环境氧气浓度下培养胚胎的潜在不利影响提供了进一步证据。
