Transcriptional levels of four Y chromosome-linked AZF genes in azoospermic men and their association with successful sperm retrieval.

Objectives: To investigate the transcriptional levels of four azoospermia factor genes in the testis of azoospermic men and to investigate the association between transcriptional levels and the results of sperm retrieval.

Methods: Thirty-eight azoospermic men with normal karyotype and without Y chromosome gene deletions were enrolled. The amounts of USP9Y (ubiquitin specific protease 9, Y chromosome), DBY (dead box on the Y), RBMY1 (RNA-binding motif on the Y, 1), and DAZ (deleted in azoospermia) transcripts were examined by quantitative competitive-reverse transcriptase-polymerase chain reaction. The steady-state concentrations of mRNA encoding for each gene in each testicular sample were normalized by the amounts of a housekeeping gene (glyceraldehyde phosphate dehydrogenase [GAPDH]). Differences in the transcript ratios (gene transcript/GAPDH transcript) among patients with different testicular histologic findings (normal spermatogenesis, hypospermatogenesis, maturation arrest, Sertoli cell-only syndrome) were analyzed. For each gene, the association between the transcript ratios and the results of sperm retrieval was evaluated.

Results: No statistically significant difference was found in the transcript ratios of USP9Y and DBY among the four histologic patient groups (P = 0.33 and P = 0.21, respectively). In contrast, statistically significant decreases were found in the transcript ratios of RBMY1 and DAZ in patients with spermatogenic failure (P = 0.0002 and P = 0.002, respectively). The transcript ratios of USP9Y and DBY were not associated with the results of sperm retrieval, and the transcript ratios of RBMY1 and DAZ revealed a positive association with successful sperm retrieval.

Conclusions: The decreased transcriptional levels of RBMY1 and DAZ in patients with spermatogenic failure may reflect the generalized loss of germ cells. The transcriptional levels of RBMY1 and DAZ may have the potential of becoming useful parameters in the prediction of successful sperm retrieval.