A triple-stain flow cytometric method to assess plasma- and acrosome-membrane integrity of cryopreserved bovine sperm immediately after thawing in presence of egg-yolk particles

Biol Reprod. 2003 May;68(5):1828-35. doi: 10.1095/biolreprod.102.011445. Epub 2002 Dec 11.

Abstract

Simultaneously evaluating postthaw viability and acrosome integrity of spermatozoa by flow cytometry would provide a valuable testing tool in both research and routine work. In the present study, a new triple-stain combination was developed for the simultaneous evaluation of viability and acrosome integrity of bovine sperm processed in egg yolk-based extender by flow cytometer. SYBR-14 and propidium iodide (PI) enabled the discrimination of sperm cells from egg yolk and debris particles, which was instrumental for the flow cytometric analyses of frozen-thawed bovine sperm, because it implied that washing steps to remove egg yolk were no longer required. In addition, phycoerythrin-conjugated peanut agglutinin (PE-PNA) was used to discriminate acrosome-damaged/reacted sperm cells from acrosome-intact cells. Repeatability was calculated using two processed ejaculates of 10 bulls. Three straws per batch were analyzed in duplicate measurements. Method-agreement analysis between the SYBR-14/PE-PNA/PI and fluorescein isothiocyanate (FITC)-conjugated PNA was performed, with FITC-PNA/PI staining being carried out on 14 frozen-thawed semen samples immediately after thawing and after a 3-h incubation at 37 degrees C. The British Standards Institution repeatability index of the SYBR-14/PE-PNA/PI combination was 2.6%. On average, the FITC-PNA/PI method showed a 6.3% overestimation of the live and acrosome-intact sperm cell subpopulation. In conclusion, the new triple-stain combination is highly repeatable and easy to use in routine application, and it provides a more precise estimate for the rate of sperm cells with intact head membrane and acrosome compared to the generally used and validated FITC-PNA/PI staining.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrosome / physiology*
  • Animals
  • Cattle
  • Cell Membrane / physiology
  • Cell Survival / physiology
  • Coloring Agents
  • Cryopreservation
  • Egg Yolk / chemistry*
  • Flow Cytometry / methods*
  • Fluorescein-5-isothiocyanate
  • Fluorescent Dyes
  • In Vitro Techniques
  • Male
  • Membranes / physiology
  • Peanut Agglutinin
  • Reproducibility of Results
  • Spermatozoa / physiology*
  • Spermatozoa / ultrastructure

Substances

  • Coloring Agents
  • Fluorescent Dyes
  • Peanut Agglutinin
  • Fluorescein-5-isothiocyanate