Proteomic analysis of rabbit fresh and cryopreserved semen provides an important insight into molecular mechanisms of cryoinjuries to spermatozoa.

Cryoinjury and protein changes are a consequence of cryopreservation and may have a negative impact on sperm quality regarding motility, viability and fertilizing ability. However, potential proteomic changes in rabbit semen throughout the cryopreservation process have never been previously investigated. The aim of the present study was to compare the whole proteome of fresh and cryopreserved rabbit semen (spermatozoa and extracellular fluid), to examine the effects of freeze-thawing on proteins changes in semen. Comparative analysis and identification of proteins was carried out using 2-dimensional difference in-gel electrophoresis coupled with a matrix-assisted laser desorption/ionization mass spectrometry. Proteomic raw data are available via ProteomeXchange with identifier PXD034832 for spermatozoa and PXD034853 for extracellular fluid. Respectively, 107 and 28 proteins differed in abundance in spermatozoa and extracellular fluid between fresh and frozen groups. Most of these proteins were involved in pathways related to energy metabolism and protein quality control under stress conditions, reproductive processes and mechanisms of cell death/survival regulation, resulting in a significant decrease of motility and viability of post-thawing rabbit sperm and its potential fertilizing ability. These results broaden the understanding of the effects of cryopreservation on rabbit semen and represent a new starting point for the development of improved freezing procedures.