This Article Full Text Full Text (PDF) All Versions of this Article: 135/5/625    most recent REP-07-0573v1 Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Cooper, T G Articles by Yeung, C H PubMed PubMed Citation Articles by Cooper, T G Articles by Yeung, C H

The tonicity of murine epididymal spermatozoa and their permeability towards common cryoprotectants and epididymal osmolytes

¹ Institute of Reproductive Medicine of the University, Domagkstrasse 11, D-48129 Münster, Germany² Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, USA

Correspondence should be addressed to T G Cooper; Email: trevorg.cooper{at}ukmuenster.de

The permeability of murine cauda epididymidal spermatozoa was determined from the swelling caused by penetrating agents at isotonicity, which lies between 422 and 530 mmol/kg. Spermatozoa were permeable to a range of solutes with size <200 Da. Relative entry rates of cryoprotective agents (CPAs) were ethylene glycolDMSO>propane-1,2-diol>glycerol>propane-1,3-diol. More polar compounds including major epididymal secretions were impermeant. None of the compounds entered spermatozoa through quinine-sensitive channels; rather, quinine increased the size of solute-swollen spermatozoa, suggesting that regulatory volume decrease and osmolyte loss occurred under these conditions. Volume responses to lowered osmolality revealed a greater volume-regulating ability of spermatozoa from the B6D2F1 strain than the C57BL6 strain. As the former strain displays better post-thaw fertility, their spermatozoa may have greater osmolyte loads enabling them to cope better with osmotic stress. Inadequate volume regulation, due to CPA-induced osmolyte loss, may affect post-thaw fertility. Knowing the permeability towards cryoprotectants will help to make a better choice of CPAs that are less damaging to sperm during cryopreservation.