Exposure of mouse oocytes to 1,2-propanediol during slow freezing alters the proteome.

Objective: To examine the effect of exposure to 1,2-propanediol (PrOH) on the mammalian oocyte proteome.

Design: Experimental study.

Setting: Research laboratory.

Animal(s): Four- to five-week-old F1 (C57BL/6 x CBA/Ca) female mice.

Intervention(s): Analysis by time-of-flight mass spectrometry.

Main Outcome Measure(s): Protein profiles of denuded mouse metaphase II (MII) oocytes.

Result(s): Metaphase II oocytes exposed to 1.5 M PrOH for 20 minutes with or without seeding (i.e., equilibration, dehydration with or without seeding) exhibited significantly altered protein profiles in comparison to controls (i.e., 37 degrees C for 20 minutes and room temperature for 20 min). In total, 11 protein-biomarkers displayed profiles of statistically significantly lower abundance, whereas 8 protein-biomarkers were observed to be statistically significantly up-regulated. Protein profiles of MII oocytes maintained at room temperature for 20 minutes were more similar to those that were incubated for 20 minutes at 37 degrees C.

Conclusion(s): Analysis of the mouse MII oocyte at different stages of the slow-freezing protocol revealed a negative impact on oocyte physiology after PrOH exposure. In contrast, temperature changes per se (during cooling to room temperature) have limited effect on the oocyte proteome.