1. Inflammogenic effect of polyacrylic acid in rat lung following intratracheal instillation
- Author
-
Chinatsu Nishida, Taisuke Tomonaga, Hiroto Izumi, Ke-Yong Wang, Hidenori Higashi, Toru Ishidao, Jun-ichi Takeshita, Ryohei Ono, Kazuki Sumiya, Shota Fujii, Shinichi Mochizuki, Kazuo Sakurai, Kei Yamasaki, Kazuhiro Yatera, and Yasuo Morimoto
- Subjects
Male ,Research ,Health, Toxicology and Mutagenesis ,Organic chemicals ,Acrylic Resins ,General Medicine ,respiratory system ,HD7260-7780.8 ,Toxicology ,Rats, Inbred F344 ,Rats ,Cross-linked polyacrylic acid (CL-PAA) ,RA1190-1270 ,Toxicology. Poisons ,Animals ,Pulmonary toxicity ,Industrial hygiene. Industrial welfare ,Bronchoalveolar Lavage Fluid ,Lung - Abstract
Background Some organic chemicals are known to cause allergic disorders such as bronchial asthma and hypersensitivity pneumonitis, and it has been considered that they do not cause irreversible pulmonary fibrosis. It has recently been reported, however, that cross-linked acrylic acid-based polymer, an organic chemical, might cause serious interstitial lung diseases, including pulmonary fibrosis. We investigated whether or not intratracheal instillation exposure to cross-linked polyacrylic acid (CL-PAA) can cause lung disorder in rats. Methods Male F344 rats were intratracheally instilled with dispersed CL-PAA at low (0.2 mg/rat) and high (1.0 mg/rat) doses, and were sacrificed at 3 days, 1 week, 1 month, 3 months and 6 months after exposure to examine inflammatory and fibrotic responses and related gene expressions in the lungs. Rat lungs exposed to crystalline silica, asbestos (chrysotile), and NiO and CeO2 nanoparticles were used as comparators. Results Persistent increases in total cell count, neutrophil count and neutrophil percentage, and in the concentration of the cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2 and C-X-C motif chemokine 5 (CXCL5), which correlated with lung tissue gene expression, were observed in bronchoalveolar lavage fluid (BALF) from 3 days until at least 1 month following CL-PAA intratracheal instillation. Persistent increases in heme oxygenase-1 (HO-1) in the lung tissue were also observed from 3 days to 6 months after exposure. Histopathological findings of the lungs demonstrated that extensive inflammation at 3 days was greater than that in exposure to silica, NiO nanoparticles and CeO2 nanoparticles, and equal to or greater than that in asbestos (chrysotile) exposure, and the inflammation continued until 1 month. Fibrotic changes also progressed after 1 month postexposure. Conclusion Our results suggested that CL-PAA potentially causes strong neutrophil inflammation in the rat and human lung.
- Published
- 2022