This study was conducted to evaluate the effect of maternal exposure to TiO2 nanoparticles on the pain response in offspring mice. 30 female mice with a mean ± SD weight of 30 ± 5 g were randomly divided into three groups: the control group (group 1) received only the basal diet; the sham group (group 2) received saline plus as a carrier (100 μL/mice) subcutaneously on days 3, 7, 10, and 14 post-mating; and the test group (group 3) received 100 μL/mice TNPs subcutaneously on days 3, 7, 10, and 14 post-mating. Offspring were divided into 6 groups 21 days after birth and underwent formalin test. Blood samples were taken to evaluate possible oxidative changes in total antioxidant capacity (TAC) and malondialdehyde (MDA). Exposure to TNPs significantly (p < 0.05) decreased pain perception. Except for a significant difference between the sham group and the control group, MDA and TAC were not significantly different among the studied groups. Injection of TNPs to pregnant mice would affect the pain perception in their offspring. This may be attributable to the ability of these particles to pass through the placenta to produce free radicals.
Keywords: NPs; formalin test; offspring; pain; titanium dioxide.