ABSTRACT
Introduction: Titanium dioxide nanoparticles (TiO2 NPs) are commonly used in industry (e.g. cosmetics, sunscreens, food
products, paints and drugs). But, they have different adverse cellular effects including oxidative stress and cellular damage.
Aim of the work: To evaluate the possible toxic effect of titanium dioxide nanoparticles on the structure of the spleen of rats.
Materials and Methods: Forty-five adult male rats were divided into three groups. Group I served as the control group.
Group II (low-dose group) rats were given oral dose of TiO2 (600 mg/kg/day) daily for 8 weeks. Group III (high-dose
group) rats were given a daily oral dose of TiO2 (1200 mg/kg/day) for 8 weeks. Spleen specimens were taken after 4 weeks,
8 weeks and 12 weeks from the start of the experiment. Thereafter, spleen specimens were processed for histological and
immunohistochemical examinations.
Results: The low-dose group showed slight disturbance in architecture of white pulp, slight congestion in red pulp and
significant increase (P< 0.01) in CD4 and CD68 immuno-expression only after 8 week specimens compared with control
group. The high-dose group showed marked disturbance in architecture of white pulp and significant increase (P< 0.01) in
CD4 and CD68 immuno-expression after 4 week specimens, CD4 and CD68 immuno-expression significantly decreased
(P< 0.01) in the 8 and in the 12 week specimens. No obvious improvement occurred after 12 weeks (withdrawal specimens).
Conclusion: Prolonged exposure to daily high oral dose of TiO2 NPs has deleterious and toxic effects on the spleen of rat,
besides disruption of its structure.