Improvements and short-term viability of mouse epididymal spermatozoa recovered through the Spermprep ™ filtration method

Abstract

This study was designed to determine the effects of Sephadex filtration (Spermprep ™I method) on the separation of motile, morphologically normal, mouse epididymal spermatozoa and to study the viability of the recovered spermatozoa over a 3-h incubation period. Spermatozoa were harvested from the caudae epididymie (5 animals per run or replication; n=10) following bilateral testicular excision, after which they were incubated in 2-ml of Test-Yolk buffer (TYB) at 37°C for 15-min. The specimens were then split into 2 1-ml aliquots, with Aliquot 1 as the control and Aliquot 2 as the filtered sample. The Spermprep ™I column was employed according to the manufacturer's specifications using TYB. During filtration (10-min), 2 different fractions were obtained: first 5-min (Sample 1) and second 5-min (Sample 2). The 2 fractions were evaluated and incubated at 37°C and assessed for percentage of motility and grade of motility (0 to 4) every 30-min for 3-h. Filtration resulted in a significant improvement in the percentage and grade of motility (91.5% and 3.0 vs 76.5% and 2.5, respectively). The results indicate that filtration with the Spermprep ™I method improved the percentage and grade of motility (P<0.05) but not the percentage of normal morphology of the spermatozoa. In addition, the Spermprep ™I method enabled the recovery of 45% (8.3 × 10 6 spermatozoa recovered) of the total number of spermatozoa processed in the control aliquot (18.4 × 10 6 spermatozoa), which is consistent with previous observations. Most importantly, filtered spermatozoa incubated for 3-h showed a greater percentage and grade of motility than the control spermatozoa (63% and 1.66 vs 39% and 0.82, respectively. The Spermprep ™I filtration method selected a higher proportion of quality spermatozoa, which also displayed significant long-term motility (longevity) during in vitro incubation.