Background: Nanosized titanium dioxide (TiO2) particles are among the most widely used nanoparticles (NPs) worldwide due to their unique properties. The lingual mucosa is still neglected in terms of risk assessment with respect to the NP uptake.
Objectives: The aim of this study was to evaluate the effect of intragastric administration of TiO2 NPs on the mucous membranes of the tongues of albino rats, as well as the potential benefits of a 4-week recovery period.
Material and methods: Twenty-one male albino rats were randomly divided into 3 groups (n = 7 per group). Group I served as a control group and received saline intragastrically daily for 30 days. The experimental groups included group II, which received TiO2 NPs in the amount of 50 mg/kg of body weight (b.w.) intragastrically daily for 30 days, and group III, which also received TiO2 NPs in the amount of 50 mg/kg b.w. intragastrically daily for 30 days, and then was allowed to recover for 4 weeks. Tongue specimens were collected for histological, immunohistochemical and morphometric examinations.
Results: The TiO2 NP group II showed significant atrophic and degenerative changes in the tongue mucosa, which included reduced epithelial thickness in the ventral surface, with disfigurement in the filiform and fungiform papillae. Weak B cell lymphoma-2 (Bcl-2) immunoreactivity was also noted. The 4-week recovery group displayed improvement in the histological picture, with moderate to strong Bcl-2 immunoreactivity in the epithelial cell layers and the underlying connective tissue.
Conclusions: The use of TiO2 NPs caused severe histological and apoptotic changes in the filiform and fungiform papillae, and the ventral surface of the tongue of the rats, while allowing recovery minimized the toxic effect of the NPs.
Keywords: Bcl-2; nanoparticle; rats; titanium; titanium dioxide.