Bis-(2-ethylexhyl) phthalate impairs spermatogenesis in zebrafish (Danio rerio).

Bis-(2-ethylhexyl) phthalate (DEHP) is a widely used industrial additive for increasing plastic flexibility. Its metabolites are known to exert toxic effects on reproduction and development of mammals. The aim of this study was to evaluate the effects of environmentally relevant concentrations of DEHP (0.2 and 20 µg/L) on the reproductive biology of adult male zebrafish (Danio rerio). The effects of DEHP and 17ß-ethynylestradiol (a positive control) were determined after one or three weeks of exposure by TUNEL assay, histomorphometric analysis and evaluation of reproductive performance. DEHP impaired reproduction in zebrafish by inducing a mitotic arrest during spermatogenesis, increasing DNA fragmentation in sperm cells and markedly reducing embryo production (up to 90%). In conclusion, relatively short-term exposure to environmentally relevant concentrations of DEHP is able to alter spermatogenesis and affect reproduction in zebrafish.

Anomalies in sperm chromatin packaging: implications for assisted reproduction techniques.

Sperm protamine deficiency and DNA damage were analysed employing chromomycin A(3) (CMA(3)) staining and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling assay, respectively, in 132 patients (82 IVF, 50 intracytoplasmic sperm injection [ICSI]). The antioxidant ability of seminal plasma was analysed in 10 men, using the total oxidant scavenging capacity assay. A significant negative correlation was found between abnormal protamination and sperm parameters, including sperm DNA fragmentation (P < 0.01). A close relationship was found between sperm protamination and fertilization and pregnancy only in IVF (P = 0.004 and P < 0.04, respectively); in ICSI there was a correlation between DNA fragmentation and pregnancy (P = 0.031). Finally, there was a negative correlation between chromatin under-protamination and the antioxidant ability of seminal plasma (P < 0.01). Results of this study underline that, despite sperm abnormal protamination and DNA fragmentation being positively correlated, they affect the reproductive outcome in different ways: in particular there was good prognostic value for CMA(3) analysis only in IVF, whereas DNA fragmentation analysis was prognostic only for ICSI outcome. Data are also provided to support the idea of a relationship between defective antioxidant system activity and impairment of chromatin packaging.

Relation between serum xenobiotic-induced receptor activities and sperm DNA damage and sperm apoptotic markers in European and Inuit populations.

Persistent organic pollutants (POPs) can interfere with hormone activities and are suspected as endocrine disrupters involved in disorders, e.g. reproductive disorders. We investigated the possible relation between the actual integrated serum xenoestrogenic, xenoandrogenic and aryl hydrocarbon receptor (AhR) activities, and the sperm DNA damage and sperm apoptotic markers of 262 adult males (54 Inuits from Greenland, 69 from Warsaw (Poland), 81 from Sweden, and 58 from Kharkiv (Ukraine)) exposed to different levels of POPs. Xenobiotic-induced receptor activities were determined by receptor-mediated luciferase reporter gene expression. Sperm DNA damage was measured using terminal deoxynucleotidyl transferase-driven dUTP nick labeling assay (TUNEL) and pro- (Fas) and anti-apoptotic (Bcl-xL) markers were determined by immune methods. Different features of xenobiotic-induced receptor activity in serum and sperm DNA fragmentation and apoptotic markers existed between the Inuits and the European Caucasians. Negative correlations between xenobiotic-induced receptor activities and DNA damage were found for Inuits having relatively lower xenoestrogenic, lower dioxin-like activity, and lower sperm DNA damage, but higher xenoandrogenic activity. In contrast, in the European groups, xenobiotic-induced receptor activities were found to be positively correlated with the DNA damage. Further research must elucidate whether altered receptor activities in concerted action with genetic and/or nutrient factors may have protecting effect on sperm DNA damage of the Inuit population.