Articles scientifiques
Leon M McClusky (2008)
Cadmium accumulation and binding characteristics in intact Sertoli/germ cell units, and associated effects on stage-specific functions in vitro: insights from a shark testis model
Journal of Applied Toxicology, 28(2):112-121.
The increased human use of cadmium (Cd) and its increased occurrence in the environment is of concern. The testis is sensitive to Cd because of the steroid-mediated regulation of spermatogenesis, high levels of DNA synthesis and gene transcription, all of which varies in a stage-related manner. Validated techniques (acridine orange vital staining to detect apoptosis and dextran-rhodamine exclusion to assess blood-testis barrier function) were recently developed and the shark testis was proposed as an alternative model for assessing stage-specific functions in living testicular tissue and to study toxicant actions on spermatogenesis. The present paper shows that 109Cd accumulation and binding in vitro was stage-dependent (premeiotic, PrM meiotic, M postmeiotic, PoM), rapid and persisted in spermatocysts (intact germ cell/Sertoli cell units) 49 h after washout. In competitive binding analyses of all three spermatocyst stages, Hg, but not Zn, could replace bound 109Cd, suggesting that Cd binding was specific. These findings were associated with a biphasic apoptotic response in the PrM spermatocysts, which was maximal at 10 microm CdCl2 and 1 microm CdCl2 after 2 and 4 days in culture, respectively. Although Cd uptake in PoM cysts was more than 2-fold less than uptake in PrM cysts, the percentage dextran-rhodamine permeant PoM cysts was approximately 8-fold greater than in controls in the presence of both 10 microm CdCl2 and 30 microm CdCl2 after 4 days culture, indicating that blood-testis barrier function in PoM spermatocysts was compromised. These findings demonstrate that this model has utility for use in screening assays of environmental toxicants.
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