Titanium Dioxide Nanoparticles: Effects on Development and Male Reproductive System

Titanium dioxide nanoparticles (TiO2-NPs) are used intensively. Thanks to their extremelysmall size (1-100 nm), TiO2-NPs are more absorbable by living organisms; consequently, they cancross the circulatory system and then be distributed in various organs including the reproductiveorgans. We have evaluated the possible toxic effect of TiO2-NPs on embryonic development andthe male reproductive system using Danio rerio as an organism model. TiO2-NPs (P25, Degussa)were tested at concentrations of 1 mg/L, 2 mg/L, and 4 mg/L. TiO2-NPs did not interfere withthe embryonic development of Danio rerio, however, in the male gonads the TiO2-NPs caused analteration of the morphological/structural organization. The immunofluorescence investigationshowed positivity for biomarkers of oxidative stress and sex hormone binding globulin (SHBG), bothconfirmed by the results of qRT-PCR. In addition, an increased expression of the gene responsiblefor the conversion of testosterone to dihydrotestosterone was found. Since Leydig cells are mainlyinvolved in this activity, an increase in gene activity can be explained by the ability of TiO2-NPs to actas endocrine disruptors, and, therefore, with androgenic activity.