Comparative cryopreservation and capacitation of spermatozoa from epididymides and vasa deferentia of the domestic cat.
Methods of cryopreservation for spermatozoa from domestic cat epididymides and vasa deferentia were compared as models for posthumous gamete salvage from non-domestic felids. Spermatozoa were collected either immediately after castration (Fresh, n = 37) or after being cooled (5 degrees C) in tissue overnight (Cool, n = 37) and released into one of three extenders containing 20% egg yolk and 3% glycerol for cryopreservation: (1) TE: Tris buffer, citric acid and fructose; (2) TC: Tris buffer, citric acid and glucose, or (3) CP: lactose, and frozen over lipid nitrogen. Before and after freezing, each sperm cell sample was evaluated for motility and percentage morphologically normal cells. Samples were also evaluated for their ability to initiate fertilization using a zona attachment assay. Neither percentage morphologically normal spermatozoa nor percentage motility differed among the three diluents for prefreeze and post-thaw samples, regardless of the collection treatment. However, CP tended to provide lower post-thaw status than did the TE and TC cryoextenders. Before freezing, there was no difference in percentage motility between the Fresh and Cool groups (mean: 76 versus 72%, respectively); however, progressive status and normal morphology were lower (P < 0.05) in Cool (3.0 and 57%) than in Fresh (3.4 and 64%) samples. After thawing there was a greater decline (P < 0.05) in percentage motility in the Cool than in the Fresh group (34 versus 24%) and the number of intact acrosomes dropped from prefreeze values of 66.7 +/- 6.3 and 56.4 +/- 4.8% to 17.8 +/- 3.9 and 20.9 +/- 4.6% after thawing in the Fresh and Cool groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)