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The sperm of sterlet (Acispenser ruthenus) was used to investigate the effect of the xenobiotic tetrabrombisphenol A (TBBPA) on sperm quality variables (ATP content, spermatozoa motility, and velocity), DNA integrity, and oxidative stress indices. Sperm was diluted to obtain a spermatozoa density of 5 × 10(8) cells/mL and exposed for 2 h to final concentrations of TBBPA (0.5, 1.75, 2.5, 5, and 10 μg/L). The oxidative stress indices, including lipid peroxidation, carbonyl derivatives of proteins, and antioxidant activity were significantly higher with increased concentrations of TBBPA. There was significantly less intracellular ATP in sperm samples at TBBPA concentrations of 2.5 μg/L and above. Spermatozoa velocity and percent motile sperm were significantly lower at each sampling time post-activation compared to controls. DNA damage expressed as percent DNA in Tail and Olive Tail moment was significantly higher with exposures ≥2.5 μg/L TBBPA. The results demonstrated that TBBPA and other xenobiotics can induce reactive oxygen species stress in fish spermatozoa, which could impair the sperm quality, DNA integrity, ATP content, and the antioxidant defense system. This study confirmed that fish spermatozoa can be used in in vitro assays for monitoring residual pollution in aquatic environments.

The effect of reactive oxygen species production on the motility parameters, DNA integrity, acid phosphatase activity, and protein tyrosine phosphorylation in spermatozoa of the common carp (Cyprinus carpio) was investigated. Spermatozoa were exposed to different concentrations of xanthine and xanthine oxidase (X-XO) either in the presence or absence of antioxidants for 15 and 60 min. A dose- and time-dependent reduction in spermatozoa motility and velocity was observed. Comet assays showed a dramatic increase in DNA fragmentation after 15 min. Changes in tyrosine phosphorylation of spermatozoa proteins were observed by Western blotting with anti-phosphotyrosine antibodies, and proteins of interest were identified by mass spectrometry. After a 60 min exposure to X-XO, O-linked N-acetylglucosamine transferase, isoform 4 was phosphorylated and septin-8-A was dephosphorylated. Acid phosphatase activity also decreased in a dose-dependent manner after a 60 min exposure to oxidative stress. The results demonstrate that oxidative stress impaired functional variables (sperm motility, velocity, DNA integrity) of carp spermatozoa, and altered intracellular signalling pathways through changes in tyrosine phosphorylation and acid phosphatase activity.