Objective:To assess the expression patterns of SAM68 in the testes of azoospermic patients with normal and abnormal spermatogenesis.
Design:Retrospective study and in vitro study.
Setting:University hospital.
Patient(s):Testicular biopsies of azoospermic men with normal spermatogenesis (OAZ; n=20), with maturation arrest at the spermatocyte stage (MA; n=20), and with Sertoli cell-only syndrome (SCOS; n=10).
Intervention(s):No interventions with patients. Knockdown of Sam68 was performed in the GC-2spd(ts) cell line.
Main outcome measure(s):SAM68 expression was analyzed using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and immunohistochemistry analysis in tissues. Moreover, Sam68 was knocked down in GC-2spd(ts) cells. Cell viability was measured using the MTT assay, and the apoptosis rate was detected using flow cytometry with the Annexin V-FITC kit.
Result(s):Using qRT-PCR, the expression level of testicular SAM68 mRNA in MA and SCOS patients was statistically reduced compared with in OAZ patients. In addition, using qRT-PCR, Western blot, and immunohistochemistry analyses, mRNA and protein expressions of SAM68 were absent or barely detectable in testicular tissues in 45% (9 of 20) of patients with MA and in all patients with SCOS. Furthermore, decreased expression of Sam68 suppressed germ cell proliferation and induced apoptosis in transfected GC-2spd(ts) cells.
Conclusion(s):Deficient SAM68 expression was observed in the human testis with MA at the spermatocyte stage and SCOS. These results may offer new perspectives on the molecular basis of abnormal spermatogenesis.
