Messenger RNA transcripts of the meiotic regulator BOULE in the testis of azoospermic men and their application in predicting the success of sperm retrieval

Background: Testicular sperm retrieval can lead to paternity for azoospermic patients with spermatogenic failure. The human BOULE gene, a meiotic regulator of germ cells, is a gene whose altered expression may be associated with sterility. We determined the levels of BOULE transcripts in the testes of azoospermic patients, and evaluated the relationship between BOULE transcript levels and patients' testicular phenotypes, clinical parameters and sperm retrieval results. Methods and results: BOULE transcript levels in the testes of 41 azoospermic patients were examined by quantitative competitive-reverse transcription-polymerase chain reaction. A significant decrease in BOULE transcript levels was detected in patients with spermatogenic failure, and BOULE transcript levels progressively decreased with increasing severity of testicular failure. BOULE transcript levels did not correlate with the serum hormone parameters measured. Significantly higher BOULE transcript levels were detected in 19 patients with successful sperm retrieval than in 12 patients with failed sperm retrieval. When using a cut-off value of 0.5 for BOULE transcript ratio to predict the success of sperm retrieval, both the sensitivity and specificity value were 100%. Conclusions: We suggest the BOULE transcript plays an important role in human spermatogenesis and that the levels may predict the presence of testicular sperm in patients with spermatogenic failure.