Nanostructured Titanium Dioxide (TiO₂) Reduces Sperm Concentration Involving Disorder of Meiosis and Signal Pathway.

Nano-titanium dioxide (nano-TiO₂) has been widely used in food and cosmetic industries, and the medical sector. However, nano-TiO₂ is potentially toxic to the reproductive system. Previous research has shown that nano-TiO₂ can reduce sperm concentration but do not yet known whether this effect occurs because of dysfunctional meiosis in spermatogenic cells. In the present paper, we demonstrate that Nano-TiO₂ can penetrate through the blood-testis barrier of a mouse model and enter the testicular tissue, thus causing damage to the testis and epididymis. This reduced the number of developing sperm; we demonstrated that the mechanism underlying this effect was the inhibition or destruction of meiosis in spermatogenic cells, particularly during meiosis I. We also found that the inhibition of meiosis I caused by nano-TiO₂ exposure was related to dysfunctional meiosis and that the abnormal expression of meiosis-related factors. Therefore, our data demonstrate that nano-TiO₂ reduces sperm concentration by disrupting meiosis and related signaling pathways.