ABSTRACT
There is a wide application of titanium dioxide [TiO[2]] nanoparticles [NPs] in industry. These particles are used in various products, and they also has biological effects on cells and organs through direct contact. In this experimental research, the effect of TiO[2] on chondrogenesis of forelimb buds of mice embryos was assessed in in vivo condition. Concentrations of 30, 150 and 500 mg/kg body weight [BW] TiO[2] NPs [20 nm size] dissolved in distilled water were injected intraperitoneally to Naval Medical Research Institute [NMRI] mice on day 11.5 of gestation. On day 15, limb buds were amputated from the embryos and skeletogeneis of limb buds were studied. TiO[2] NPs caused the significant changes in chondrocytes in the following developmental stages: resting, proliferating, hypertrophy, degenerating, perichondrium and mesenchymal cells. Decreased number of mesenchymal cells and increased level of chondrocytes were observed after the injection of different concentrations of TiO[2], which proves the unpredictable effects of TiO[2] on limb buds. Results of the present study showed TiO[2] NPs accelerated the chondrogenesis of limb buds, but further studies are recommended to predict TiO[2] toxicity effects on organogenesis