Rate of homologous chromosome bivalents in spermatocytes may predict completion of spermatogenesis in azoospermic men.

Abstract. The rate of bivalent formation during meiosis was correlated with the presence and amount of spermatozoa in the testes of azoospermic men. Four pairs of chromosomes, X-Y, 9, 15, and 18, were evaluated. In addition, left and right testes were compared. Three biopsies from each testis were undertaken to extract spermatozoa for intracytoplasmic sperm injection. In addition, one sample from each testis was used for histological definition, spermatozoa count and detection of chromosome bivalents in spermatocytes. A significantly higher rate of bivalents of all homologous chromosomes was found whenever spermatozoa were detected. The rate of bivalent X-Y was found to be the most sensitive predictor for detection of spermatozoa, with a cut-off value of 47%. The R(2) was 27% ( P=0.003) for the percent of spermatozoa in the minced sample as well as the number of mature spermatids per tubule in the histological section. All pairs of testes were in concord in regard to the likelihood of finding spermatozoa. In the testes where no spermatozoa were found on biopsy, the rate of X-Y bivalent indicated the presence of spermatozoa in the opposite side. Thus, it may be concluded that the rate of X-Y bivalent formation in spermatocytes may predict the presence and amount of spermatozoa in the testicular tissue of azoospermic men. It is suggested that when no spermatozoa are located by testicular fine-needle aspiration, X-Y bivalent evaluation may be conducted if spermatocytes are evinced. A high rate of X-Y bivalents may impel one to continue with testicular open biopsies.