Impairment of sperm efficiency in mice following short-term nano-titanium dioxide exposure: An experimental study

Abstract

Background: Titanium dioxide nanoparticles (TiO2NPs) are widely used in many compounds. Recent evidence has displayed some cytotoxic effects of TiO2NPs on male reproduction. Objective: The effects of TiO2NP administration on sperm parameters and chromatin and seminiferous histopathology of male mice were investigated. Materials and Methods: In this experimental study, 32 NMRI male mice (35 ± 3 gr, 8-12-week-old) were divided into four groups (n = 8/each): treated groups were fed orally with 2.5 (group I), 5 (group II) and 10 (group III) mg/kg/day TiO2NPs for 40 days and the control group received phosphate buffered saline. Sperm parameters, DNA integrity and chromatin quality were assessed using chromomycin A3, aniline blue, toluidine blue staining and TUNEL. Hematoxylin eosin staining was performed to measure spermatogenic cells and the total diameter of seminiferous tubules. Also, sex hormone and malondyaldehyde levels were measured. Results: Abnormal sperm tails rose in group III (28.87 ± 4.91) in comparison with the control group (12.75 ± 3.95). However, chromomycin A3 staining and TUNEL showed higher levels in group III in comparison with the control group, whereas aniline blue and toluidine blue staining showed no differences. A significantly lower spermatogenesis index and lumen parameters were observed in group III. Leydig cell numbers, cellular diameters and the area of the seminiferous tubules were lower in the treated groups. The testosterone level was also lower in these groups and the percentage of malondyaldehyde in the seminal fluid was higher. Conclusion: Exact mechanisms of TiO2NPs are not clear; however, cytotoxic and genotoxic effects of TiO2NPs may relate to oxidative stress. Given their widespread use, TiO2NPs should be a public health focus of attention. Key words: Titanium dioxide, Spermatogenesis, Histology, Mouse, Chromatin, TUNEL.