Effects of oral administration of titanium dioxide particles on sperm ‎parameters and in vitro fertilization potential in mice: A comparison ‎between nano- and fine-sized particles

Titanium dioxide particles (TiO2) as the second most widely used materials in consumer products are composed of nano-sized (100 nm) particles (FPs). Toxicological studies on animals have shown that TiO2 NPs exposure can cross the blood-testis barrier and accumulate in the testis resulting in testicular tissue damage and reduction of sperm count and motility. However, there is no information on the toxic effects of TiO2 FPs on male reproductive fertility. Twenty-four adult male mice were randomly divided into three groups including control, TiO2 NPs, and TiO2 FPs (150 mg kg-1 per day). After intragastric administration for 35 days, testicular tissue alterations (seminiferous tubule diameter and germinal epithelial height), sperm parameters (count, motility, viability, morphology, and DNA quality), in vitro fertilization potential, oxidative stress assays such as malondialdehyde (MDA) content, level of glutathione (GSH) and activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in testicular tissue were investigated. The results showed that both sizes of TiO2 caused pathologic changes in the testis and significantly increased MDA level and decreased GSH levels and activities of SOD and GPx in testicular tissue. Moreover, the administration of both sizes of TiO2 significantly decreased all of the sperm parameters and in vitro fertility (fertilization rate and pre-implantation embryos development) compared to control. Administration of TiO2 FPs similar to TiO2 NPs through inducing damages to testis led to a marked reduction in sperm quality, in vitro fertilization, and embryos development in male mice.