Ultrastructure of pneumonocyte in female mice lung caused by nasal administration of nano-TiO2 for 90 consecutive days.

(a) Control: chromatin is well distributed, normal lamellar bodies; (b) 2.5 mg/kg BW nano-TiO2 indicates a significant shrinkage and chromatin marginalization of the nucleus (yellow arrows), mitochondria swelling(red arrows); (c) 5 mg/kg BW nano-TiO2 indicates a significant nucleus pyknosis (green arrows); (d) 10 mg/kg BW nano-TiO2 indicate a significant nucleus pyknosis (yellow arrows), mitochondria swelling(red arrows) as well as evacuation of lamellar bodies (green arrows), circles show black deposition. Arrow A spot is a representative cell that not engulfed the nano-TiO2, while arrow B spot denotes a representative cell that loaded with nano-TiO2. (c) The right panels show the corresponding Raman spectra identifying the specific peak at about 148 cm−1.