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Updated: Aug 11, 2026

Sperm Collection of Differential Quality Using Density Gradient Centrifugation
Published on: November 29, 2018
Interrelationships between seminal parameters and sperm nuclear DNA damage before and after density gradient
M J Tomlinson1, O Moffatt, G C Manicardi
1Assisted Conception Unit, Birmingham Women's Hospital, Birmingham, UK.
Background:
With an increase in the use of assisted reproduction technologies the requirements of the diagnostic semen analysis are constantly changing.
Methods:
Spermatozoa from patients undergoing IVF were analysed by examining the conventional semen parameters and DNA/chromatin integrity, using in-situ nick translation (NT) and the Chromomycin A(3) fluorochrome, which indirectly demonstrates a decreased presence of protamine. Samples were examined before and after preparation using discontinuous density gradient centrifugation.
Results:
Density gradient centrifugation enriched samples by improving the percentage of morphologically normal forms by 138% and sperm nuclear integrity by 450%. Sperm nuclear integrity as assessed by in-situ nick translation (NT) demonstrated a very clear relationship with sperm concentration, motility and morphology. Morphology correlated with fertilization rates of patients undergoing IVF, while NT values of the spermatozoa post-preparation were significantly lower in pregnant patients.
Conclusions:
We have demonstrated that along with the classical semen parameters, the assessment of nuclear integrity improves the characterization of the semen sample and may be used as a tool for allocating patients to specific assisted reproduction treatments.
Related Concept Videos
Spermatogenesis
Fertilization
Centrifugation

