Evidence of reduced single-stranded testicular sperm DNA from obstructive azoospermic men after 3 days of in-vitro culture

The aim of the present study was to verify whether culturing testicular tis sue, to obtain a higher percentage of motile spermatozoa and a better post- thaw recovery rate, affected the ratio between single/double-stranded sperm DNA and, consequently, DNA sensitivity to damage, Testicular biopsy sample s from men with obstructive and secretory azoospermia, candidates for assis ted reproductive treatment, were cultured for 72 h, The percentage of motil e spermatozoa and the single/double stranded DNA ratio were assessed on the day of retrieval (day 0) and again on day 3, The single/double stranded DN A ratio was measured by the acridine orange (AO) staining method, Spermatoz oa were classified as green (double-stranded chromatin) or red fluorescing (single-stranded chromatin), In obstructive azoospermia, median motility wa s 22% (range 10-44%) on day 0 and 50% (range 38-63%) on day 3 (P < 0.01), T he median percentage of red stained spermatozoa was 53.5% (range 0.1-88%) o n day 0 and 20% (range 2.7-99.9%) on day 3 (P < 0.05), No changes were obse rved in secretory azoospermia, The culture procedure from obstructive azoos permia not only increased the post-thaw recovery rate, as previously observ ed, but also reduced the portion of spermatozoa containing single-stranded DNA, thereby increasing the availability of double-stranded DNA spermatozoa for ICSI use.