Rieger D, Bruyas J F, Lagneaux D, Bézard J, Palmer E
Department of Biomedical Sciences, University of Guelph, Ontario, Canada.
J Reprod Fertil Suppl. 1991;44:411-7.
The decrease in embryo viability caused by cryopreservation may be due, in part, to metabolic disturbances. To determine the effect of cryopreservation on metabolism, Day -6.5 horse embryos were either frozen and thawed using glycerol as the cryoprotectant, given only the glycerol treatment or washed an equal number of times in phosphate buffered saline (PBS). Before and after treatment, individual embryos were incubated with L-[14C(U)]-glutamine, to measure Krebs cycle activity, and D-[5-3H]-glucose, to measure Embden-Meyerhof pathway activity. Before treatment, glucose metabolism ranged from 110-625 pmol/2 h and glutamine metabolism from 4.1-15.9 pmol/2 h, both being highly correlated with embryo volume. Mean glucose metabolism in the control group increased 76% between the pre-treatment and post treatment measurements compared with 1% in the pooled treated groups, whereas mean glutamine metabolism increased only 10% in the control group but 50% in the treated embryos. Before treatment, there was no difference in mean ratio of glucose to glutamine metabolism between groups, but after treatment this ratio was almost 2-fold greater in the control group than in the treated group. These results indicate that cryopreservation inhibits anaerobic glucose metabolism and stimulates aerobic glutamine metabolism. However, this is an effect of the cryoprotectant, rather than of freezing and thawing.
冷冻保存导致胚胎活力下降，部分原因可能是代谢紊乱。为了确定冷冻保存对代谢的影响，将第6.5天的马胚胎使用甘油作为冷冻保护剂进行冷冻和解冻处理，或仅给予甘油处理，或在磷酸盐缓冲盐水（PBS）中洗涤相同次数。在处理前后，分别将单个胚胎与L-[14C(U)]-谷氨酰胺一起孵育以测量三羧酸循环活性，与D-[5-3H]-葡萄糖一起孵育以测量糖酵解途径活性。处理前，葡萄糖代谢范围为110 - 625 pmol/2小时，谷氨酰胺代谢范围为4.1 - 15.9 pmol/2小时，两者均与胚胎体积高度相关。对照组预处理和处理后测量的平均葡萄糖代谢增加了76%，而合并处理组仅增加了1%，而对照组平均谷氨酰胺代谢仅增加了10%，但处理后的胚胎增加了50%。处理前，各组之间葡萄糖与谷氨酰胺代谢的平均比值无差异，但处理后，对照组该比值几乎是处理组的2倍。这些结果表明，冷冻保存抑制无氧葡萄糖代谢并刺激有氧谷氨酰胺代谢。然而，这是冷冻保护剂的作用，而非冷冻和解冻的作用。
