Ultrastructural analysis of chromatin defects in testicular spermatids in azoospermic men submitted to TESE-ICSI

BACKGROUND: Testicular sperm extraction (TESE) combined with intracytoplasmic sperm injection (ICSI) is offered to treat obstructive and non-obstructive azoospermia, but factors that influence the outcome of ICSI are not well defined. METHODS AND RESULTS: The percentage of elongated spermatids with normal chromatin condensation in azoospermic patients submitted for TESE-ICSI was determined. The quantitative analysis could be applied to nine of 19 biopsies classified as incomplete late maturation arrest (LMA) and compared with 10 biopsies with normal spermatogenesis. The percentage of elongated spermatids with normal chromatin was lower in LMA than in normal histology (mean 4.4%, range 0-20, and mean 52.9%, range 40-70 respectively; P = 0.0001), The percentage of elongated spermatids with normal chromatin was negatively correlated with the serum concentration of FSH (r = -0.86, P < 0.0001) and the number of degenerated germ cells per 100 Sertoli cells nuclei (r = -0.68; P < 0.0001), while it was positively correlated with the number of elongating spermatids per 100 Sertoli cell nuclei (r = 0.81; P < 0.0001), The percentage of elongated spermatids with normal chromatin was not correlated with the rate of oocyte fertilization, while the delivery rate/cycle was higher in cases with normal histology compared with cases of LMA. CONCLUSIONS: These preliminary data suggest that an altered chromatin condensation is a ubiquitous defect in spermatids of non-obstructed azoospermic men submitted for TESE-ICSI.