Comparative study on the acute pulmonary toxicity induced by 3 and 20 nm TiO 2 primary particles in mice

Abstract

The acute pulmonary toxicity induced by 3-nm TiO 2 primary particles was preliminary investigated after they were intratracheally instilled at doses of 0.4, 4 and 40 mg/kg into lungs of mice. The biochemical parameters in bronchoalveolar lavage fluid (BALF) and pathological examination were used as endpoints to assess their pulmonary toxicity at 3-day postexposure. As such, the pulmonary toxicity assessment of 20-nm TiO 2 primary particles was performed using the same method. It was found that the 3-nm TiO 2 primary particles induced no pulmonary toxicity at dose of 0.4 mg/kg, moderate toxicity at 4 mg/kg and lung overload at 40 mg/kg, and this kind of particles did not produce more pulmonary toxicity than the 20-nm ones at any instilled doses. As regards physicochemical characteristics of the two TiO 2 particles, their pH values in medium, other than particle size, surface area and aggregation, may play important role in affecting their pulmonary toxicity.