Sex chromosome alignment at meiosis of azoospermic men with azoospermia factor microdeletion.

Deletions in the q arm of the Y chromosome result in spermatogenesis impairment. The aim of the present study was to observe the X and Y chromosome alignment in the spermatocytes of men with Y chromosome microdeletion of the azoospermia factor (AZF) region. This was performed by multicolor fluorescence in situ hybridization probes for the centromere and telomere regions. Testicular biopsies were performed in a testicular sperm extraction-intracytoplasmic sperm injection set-up in 11 azoospermic men: 8 (nonobstructive) with AZF deletions and 3 (obstructive) controls. Histological sections, cytology preparations of the testicular biopsies, and evaluation of the meiosis according to the percentage of XY and 18 bivalents formation were assessed. Spermatozoa were identified in at least one location in controls and specimens with AZFc-deleted Y chromosomes. Complete spermatocyte arrest was found in those with a deletion that included the entire AZFb region. Bivalent formation rate of chromosome 18 was high in all samples (81%-99%). In contrast, the rate of bivalent X-Y as determined by centromeric probes was lower but in the range favorable with spermatozoa findings in controls and patients with the AZFc deletion (56%-90%), but not in those with AZFb-c deletions (28%-29%). A dramatic impairment in the normal alignment of X and Y telomeres in the specimen with AZFb-c deletion was shown (29%), compared to the specimens with AZFc deletion (70%-94%). It is suggested that the absence of sperm cells in specimens with the entire AZFb and with AZFb-c deletions is accompanied by meiosis impairment, perhaps as a result of the extent of the deletion or because of the absence of genes that are involved in the X and Y chromosome alignment.

Use of sex chromosome bivalent pairing in spermatocytes of nonobstructive azoospermic men for the prediction of successful sperm retrieval.

OBJECTIVE: To find the most informative method of XY bivalent detection for spermatozoa presence in testicular tissue of nonobstructive azoospermic men. DESIGN: Prospective study. SETTING: Institute for the Study of Fertility, affiliated with a university medical faculty. PATIENT(S): Thirty-five men with azoospermia, divided into subgroups: complete maturation arrest (n = 10), mixed atrophy (n = 14), and obstructive azoospermia (n = 11). INTERVENTION(S): Testicular tissue biopsies for sperm extraction. MAIN OUTCOME MEASURE(S): Histopathologic and cytology analyses and the presence of XY bivalent formation by fluorescence in situ hybridization probes for centromere and subtelomere regions. Immunostaining of gamma-H2AX for sex body (SB) identification was also performed. RESULT(S): Percentage of spermatocytes with X-Y pairing, determined by the paired short arms pseudoautosomal region, was significantly higher than percentage of spermatocytes with long arm telomeres in proximity in all three groups. The parameter of q telomeres in proximity was the most sensitive index to distinguish one group from the other. Stained SB by gamma-H2AX was found to be the most informative for the prediction of successful sperm retrieval. CONCLUSION(S): Alignment of the X and Y axes that occurs in the late zygotene stage probably precedes the stage in which the SB is stained by gamma-H2AX. Consequently, because of the nonhomogeneity of the testis, when histology raises suspicion of complete maturation arrest percentage of spermatocytes with stained SB is the most informative parameter for sperm presence on sperm retrieval.