Effects of D-glucose concentration, D-fructose, and inhibitors of enzymes of the pentose phosphate pathway on the development and sex ratio of bovine blastocysts
Effects of D-glucose concentration, D-fructose, and inhibitors of enzymes of the pentose phosphate pathway on the development and sex ratio of bovine blastocysts
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DOI：
10.1002/mrd.20342
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发表时间：
2005-10-01
影响因子：
2.5
通讯作者：
Roberts, RM
中科院分区：
文献类型：
--
作者：
Kimura, K;Spate, LD;Roberts, RM
5.6 mM的d -葡萄糖减少了体外生产（IVP）牛胚胎从桑葚胚到囊胚期的进展，并使性别比偏向雄性。可能，两个转录活跃的x染色体的存在通过葡萄糖代谢的不平衡损害了女性胚胎的发育。在这里，我们已经确定了胚胎对葡萄糖敏感的阈值，d -果糖替代葡萄糖是否减少了雌性胚胎的选择性损失，以及x -链基因产物葡萄糖6-磷酸脱氢酶（G6PD）的抑制是否使牛囊胚的性别比例正常化。体外受精受精卵在无葡萄糖培养基中培养至授精后72小时，选择8个细胞胚胎进行处理，培养至授精后144小时。8细胞期添加4 mM葡萄糖可降低囊胚形成数（P < 0.05）， 2.5和1 mM葡萄糖无显著影响。4和2.5 mM葡萄糖存在时的性别比与0.5显著不同，而1 mM葡萄糖没有影响。d -果糖（5.6 mM）不会影响囊胚的发育，也不会改变形成的囊胚的性别比例。在含有4 mM葡萄糖的培养基中加入G6PD抑制剂（脱氢表雄酮：DHEA和6-氨基氨基酰胺：6-AN），可以有效地抑制牛毛囊中nadph敏感染料——甲酚蓝（BCB）的还原，胚胎发育适度减少，但性别比例偏差得到纠正（6-AN）或降低（DHEA）。综上所述，高于2.5 mM的葡萄糖会损害牛胚胎发育并增加性别比例，这很可能是由于雌性胚胎中戊糖-磷酸盐（PP）途径活性增加所致。
D-glucose at 5.6 mM reduces the progression of in vitro-produced (IVP) bovine embryos from the morula to the blastocyst stage and skews sex ratio towards males. Possibly, the presence of two transcriptionally active X-chromosomes compromises female embryo development through imbalance in glucose metabolism. Here, we have determined the threshold of embryo sensitivity to glucose, whether substitution Of D-fructose for glucose reduces the selective loss of female embryos, and whether inhibition of an X-linked gene product, glucose 6-phosphate dehydrogenase (G6PD), normalizes sex ratio among bovine blastocysts. IVP zygotes were cultured in glucose-free medium to 72 hr post-insemination, at which time 8-cell embryos were selected for treatment and cultured until 144 hr post-insemination. Addition of 4 mM glucose at the 8-cell stage reduced (P < 0.05) the number of blastocyst that formed, whereas 2.5 and I mM glucose had no effect. Sex ratio in the presence of 4 and 2.5 mM glucose differed significantly from 0.5, while 1 mM glucose had no effect. D-fructose (5.6 mM) did not compromise development to blastocyst and did not alter the sex ratio of blastocysts that formed. When G6PD inhibitors (dehydroepiandrosterone: DHEA and 6-aminonicotinamide: 6-AN), which effectively inhibit the reduction of the NADPH-sensitive dye, brilliant cresyl blue (BCB) in bovine morulae, were added to the culture medium containing 4 mM glucose, embryo development was moderately reduced, but sex ratio skewing was corrected (with 6-AN) or lowered (with DHEA). In conclusion, glucose above 2.5 mM impairs bovine embryo development and increases sex ratio, most likely as a result of increased pentose-phosphate (PP) pathway activity in female embryos.