TiO₂ Nanoparticle Exposure Decreases Spermatogenesis via Biochemical Dysfunctions in the Testis of Male Mice

TiO2 nanoparticles (NPs) have been demonstrated to suppress spermatogenesis in animals, while there is little data related to the biochemical dysfunctions during spermatogenesis due to exposure to TiO2 NPs. In this study, male mice have been exposed to TiO2 NPs via intragastric administration for 60 consecutive days. The findings showed that TiO2 NP exposure resulted in lesions of testis and epididymis, deductions in sperm concentration and sperm motility, and an increase of the number of abnormal sperm in mice. Furthermore, TiO2 NP exposure with 2.5, 5, or 10 mg/kgbw decreased activities of lactate dehydrogenase (-11.59% to -39.84%), sorbitol dehydrogenase (-23.56% to -57.33%), succinate dehydrogenase (-27.04% to -57.85%), glucose-6-phosphate dehydrogenase (-28.3% to -56.42%), Na(+)/K(+)-ATPase (-15.59% to -53.11%), Ca(2+)-ATPase (-12.44% to -55.41%), and Ca(2+)/Mg(2+)-ATPase (-28.25% to -65.72%), and elevated activities of acid phosphatase (+10.48% to +40.0%), alkaline phosphatase (+20.65% to +64.07%), and total nitric oxide synthase (+0.68- to +2.3-fold) in the testes of mice, respectively. In addition, TiO2 NP exposure caused excessive production of reactive oxygen species (+16.15% to +110.62%), and increased malondialdehyde of lipid peroxidation product (+38.96% to +118.07%), carbonyl of protein oxidative product (+20.98% to +108.1%), and 8-hydroxydeoxyguanosine of DNA oxidative product (+0.9- to +1.83-fold) in the testes, respectively. It implied that spermatogenesis suppression caused by TiO2 NP exposure may be associated with alterations of testicular marked enzymes and oxidative stress in the testes.