In Vitro Effects of Titanium Dioxide Nanoparticles (TiO2NPs) on Cadmium Chloride (CdCl2) Genotoxicity in Human Sperm Cells.

The environmental release of titanium dioxide nanoparticles (TiO2NPs) associated with their intensive use has been reported to have a genotoxic effect on male fertility. TiO2NP is able to bind and transport environmental pollutants, such as cadmium (Cd), modifying their availability and/or toxicity. The aim of this work is to assess the in vitro effect of TiO2NPs and cadmium interaction in human sperm cells. Semen parameters, apoptotic cells, sperm DNA fragmentation, genomic stability and oxidative stress were investigated after sperm incubation in cadmium alone and in combination with TiO2NPs at different times (15, 30, 45 and 90 min). Our results showed that cadmium reduced sperm DNA integrity, and increased sperm DNA fragmentation and oxidative stress. The genotoxicity induced by TiO2NPs-cadmium co-exposure was lower compared to single cadmium exposure, suggesting an interaction of the substances to modulate their reactivity. The Quantitative Structure-Activity Relationship (QSAR) computational method showed that the interaction between TiO2NPs and cadmium leads to the formation of a sandwich-like structure, with cadmium in the middle, which results in the inhibition of its genotoxicity by TiO2NPs in human sperm cells.

In vitro genotoxic effects of titanium dioxide nanoparticles (n-TiO2 ) in human sperm cells.

Titanium dioxide nanoparticles (TiO2 -NPs) are one of the most widely engineered nanoparticles used. The study has been focused on TiO 2 -NPs genotoxic effects on human spermatozoa in vitro. TiO 2 -NPs are able to cross the blood-testis barrier induced inflammation, cytotoxicity, and gene expression changes that lead to impairment of the male reproductive system. This study presents new data about DNA damage in human sperms exposed in vitro to two n-TiO 2 concentrations (1 µg/L and 10 µg/L) for different times and the putative role of reactive oxygen species (ROS) as mediators of n-TiO 2 genotoxicity. Primary n-TiO 2 characterization was performed by transmission electron microscopy. The dispersed state of the n-TiO 2 in media was spectrophotometrically determined at 0, 24, 48, and 72 hr from the initial exposure. The genotoxicity has been highlighted by different experimental approaches (comet assay, terminal deoxynucleotidyl transferase dUTP nick end labeling [TUNEL] test, DCF assay, random amplification of polymorphic DNA polymerase chain reaction [RAPD-PCR]). The comet assay showed a statistically significant loss of sperm DNA integrity after 30 min of exposure. Increased threshold of sperm DNA fragmentation was highlighted after 30 min of exposure by the TUNEL Test. Also, the RAPD-PCR analysis showed a variation in the polymorphic profiles of the sperm DNA exposed to n-TiO 2 . The evidence from the DCF assay showed a statistically significant increase in intracellular ROS linked to n-TiO 2 exposure. This research provides the evaluation of n-TiO 2 potential genotoxicity on human sperm that probably occurs through the production of intracellular ROS.