A comparison of inflammation elicited in animals receiving doses of UFTiO
normalized to surface area of particles administered per surface area of alveolar epithelium. A comparison of inflammation elicited in animals receiving doses (0.0313, 0.0625 and 0.125 cm2/cm2) of UFTiO2 and FTiO2 normalized to surface area of particles administered per surface area of alveolar epithelium at 1 day (Panel A), 7 days (Panel B), and 42 days (Panel C) post-exposure. Particles were suspended in BALF. Rats were exposed to various doses of UFTiO2 and FTiO2 by intratracheal instillation. Animals were euthanized at 1 day, 7 days, and 42 days post-exposure and bronchoalveolar lavage was performed. Inflammation was assessed by BAL PMN counts. Values are increased PMN number above the BALF control and are given as means ± SE of 8 experiments. Control PMN values were 1.37 ± 0.098 × 106, 0.78 ± 0.074 × 106, and 0.88 ± 0.095 × 106 cells/rat for 1, 7 and 42 days, respectively. Linear regression analysis with a 95% confidence interval reveals that, when dose is normalized to surface area of particles administered, dose responses curves assessing inflammation caused by UFTiO2 and FTiO2 exposure are not significantly different. On a dose normalized to surface area, UFTiO2 elicits at most a 2 fold increase in inflammation when compared to FTiO2 at all post-exposure times.