Histological sections through the chest wall of mice treated with long straight nanotubes (A, B) or short, tangled nanotubes (C, D) for 1 or 7 days. Note the progressive thickening of the mesothelium in A and B in response to long straight nanotubes; this contrasts with the acute thickening of the pleural layer with short/tangled CNT which shows resolution to normal mesothelium by 7 days (D). Scale bars represent 20 μm.
Donaldson et al. Particle and Fibre Toxicology 2010 7:5 doi:10.1186/1743-8977-7-5