Objective: To track the translocation of water soluble taurine multi-wall carbon nanotubes (14C-tau-MWCNTs) in lungs of the Kunming mice and evaluate the acute lung toxicity of intratracheally instilled tau-MWCNTs in Kunming mice.
Methods: Healthy adult Kunming mice were randomly grouped by their body weight (5 mice in each group). The lungs of mice were intratracheally instilled with 0.125, 0.25, 0.5 and 1 mg/kg of water soluble tau-MWCNTs and phosphate-buffered saline (PBS) as negative control. After exposure of 1, 7, 14 and 28 days, the blood and lung tissue were collected. Blood were assessed by using biochemical biomarkers of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and angiotensin converting enzyme (ACE). Lung tissues were assessed by histopathology. The intratracheal instillation of 14C-tau-MWCNTs was conducted in the same way, after 1, 3, 7, 14, 21, 28 days, 14C-activity of the samples was counted in several organs, tissues, blood and feces etc.
Results: 14C-activities were detected only in lungs, and with the exposure time proceeding the radioactivity descending from (80 +/- 7.7)% of the 1st day to (22 +/- 6.9)% of the 28th day. Activity of all groups of ALP and LDH went to the highest level on the 7th day postexposure, and back to the control level on the 28th day post-exposure, but LDH of 1 mg/kg group[(14.18 +/- 1.70) micromol x s(-1) x L(-1)] was still higher than that of control [(10.95 +/- 3.51) micromol x s(-1) x L(-1)] after 28 days' exposure. There was no significant changes observed in the activity of ACE. Histopathology found that lungs of all groups presented significant increase in pulmonary inflammation, lung cell proliferation. Many tau-MWCNTs were clearly found in some alveolar macrophages and bronchial epithelial cells.
Conclusion: Intratracheal instillation of water soluble tau-MWCNTs could induce slight bio-effects on lungs of Kunming mice.