The effect of inhaled nanoTiO2 on lung histology and serum biochemic al indexes is evaluated in healthy and adult Kunming mice (eight in each group) after exposure to TiO2 aerosols (1　500 mg／m3) in a sealed chamber. Ano ther e ight mice are exposed to indoor air to be served as a control group. Lung tissue and blood are collected after euthanizing the animals. The results show that la c tate dehydrogenase (LDH) activity increases in all experimental groups. Alanine aminotransferase(ALT) activity and blood urea nitrogen (BUN) levels are increase d in the group exposed to TiO2 aerosols for 28 d

and creatinine(Cr) level s are increased in 14 d and 28 d samples (P<005). No obvious changes are observed in other serum indexes. Lungs of mice exposed to 28 d exposure show significant but moderate increase in pulmonary inflammatio n

and many TiO2 particles are found in the interstitium of pulmonary alve oli.