Interrelationships between seminal parameters and sperm nuclear DNA damagebefore and after density gradient centrifugation: implications for assisted conception

BACKGROUND: With an increase in the use of assisted reproduction technologi es the requirements of the diagnostic semen analysis are constantly changin g. METHODS: Spermatozoa from patients undergoing IVF were analysed by exami ning the conventional semen parameters and DNA/chromatin integrity, using i n-situ nick translation (NT) and the Chromomycin A(3) fluorochrome, which i ndirectly demonstrates a decreased presence of protamine. Samples were exam ined before and after preparation using discontinuous density gradient cent rifugation. RESULTS: Density gradient centrifugation enriched samples by im proving the percentage of morphologically normal forms by 138% and sperm nu clear integrity by 450%. Sperm nuclear integrity as assessed by in-situ nic k translation (NT) demonstrated a very clear relationship with sperm concen tration, motility and morphology. Morphology correlated with fertilization rates of patients undergoing IVF, while NT values of the spermatozoa post-p reparation were significantly lower in pregnant patients. CONCLUSIONS: We h ave demonstrated that along with the classical semen parameters, the assess ment of nuclear integrity improves the characterization of the semen sample and may be used as a tool for allocating patients to specific assisted rep roduction treatments.