Case report of apoptosis in testis of four AZFc-deleted patients: increased DNA fragmentation during meiosis, but decreased apoptotic markers in post-meiotic germ cells

Hum Reprod. 2012 Jul;27(7):1939-45. doi: 10.1093/humrep/des128. Epub 2012 Apr 16.

Abstract

AZFc deletions of the Y chromosome are the major known genetic cause of spermatogenetic failure. Meiotic studies have shown a prevalence of synaptonemal complex fragmentation and an excess of early-stage sperm cells, suggesting that the maturation block could involve apoptosis. We present a prospective and observational study of apoptotic markers in the sperm of four AZFc-deleted patients and two non-obstructive azoospermic controls without an AZFc deletion. Polycaspases assays and terminal deoxynucleotidyl transferase dUDP nick-end labelling (TUNEL) assays were combined to evaluate the incidence of apoptosis in pre-meiotic, meiotic and post-meiotic germs cells identified, respectively, using anti-melanoma-associated antigen A4 (MAGE-A4), anti-synaptonemal complex protein 3 (SCP3) and anti-sperm acrosome membrane-associated protein 1 (SPACA1) antibodies. We detected apoptosis at all stages of AZFc-deletion spermatogenesis. Using the caspase assay, the incidence of positive cells was found to be heterogeneous for pre-meiotic (from 4.8 to 84.5%) and meiotic stages (from 7.9 to 57.6%), while for post-meiotic cells, the mean incidence was 6% in AZFc-deleted patients compared with 26.5% in controls (P < 0.05). Using the TUNEL assay, the mean percentage with DNA fragmentation for meiotic cells was 54.0% in AZFc-deleted patients compared with 20.3% in controls (P < 0.05), while the percentage of TUNEL-positive post-meiotic cells ranged from 5.3 to 44.7%. Spermatocyte loss in AZFc-deleted patients occurs via the apoptotic pathway. In post-meiotic cells, the lower incidence of apoptosis in testis from three of the four AZFc-deleted patients, compared with controls, is consistent with AZFc deletions having little negative impact on sperm quality.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Apoptosis*
  • Azoospermia / genetics*
  • Caspases / metabolism
  • Chromosomes, Human, Y / genetics*
  • DNA Fragmentation*
  • Enzyme Activation
  • Gene Deletion*
  • Germ Cells / cytology*
  • Humans
  • In Situ Nick-End Labeling
  • Karyotyping
  • Male
  • Meiosis*
  • Microscopy, Fluorescence / methods
  • Phenotype
  • Spermatocytes / cytology
  • Testis / pathology*

Substances

  • Caspases