Crosslinked Structure of Polyacrylic Acid Affects Pulmonary Fibrogenicity in Rats

Abstract

We conducted intratracheal instillations of polyacrylic acid (PAA) with crosslinking and non-crosslinking into rats in order to examine what kinds of physicochemical characteristics of acrylic-acid-based polymers affect responses in the lung. F344 rats were intratracheally exposed to similar molecular weights of crosslinked PAA (CL-PAA) (degree of crosslinking: ~0.1%) and non-crosslinked PAA (Non-CL-PAA) at low and high doses. Rats were sacrificed at 3 days, 1 week, 1 month, 3 months, and 6 months post-exposure. Both PAAs caused increases in neutrophil influx, cytokine-induced neutrophil chemoattractants (CINC) in the bronchoalveolar lavage fluid (BALF), and heme oxygenase-1 (HO-1) in the lung tissue from 3 days to 6 months following instillation. The release of lactate dehydrogenase (LDH) activity in the BALF was higher in the CL-PAA-exposed groups. Histopathological findings of the lungs demonstrated that the extensive fibrotic changes caused by CL-PAA were also greater than those in exposure to the Non-CL- PAA during the observation period. CL-PAA has more fibrogenicity of the lung, suggesting that crosslinking may be one of the physicochemical characteristic factors of PAA-induced lung disorder.

The Effects of Endoplasmic Reticulum Stress via Intratracheal Instillation of Water-Soluble Acrylic Acid Polymer on the Lungs of Rats

“…A sample of PAA was synthesized via polymerization of an acrylic acid monomer without a cross-linking agent, as in our previous report [39]. Reversible addition/cleavage chain transfer polymerization was carried out using 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl] pentanoic acid (CDP, Sigma Aldrich, St. Louis, MO, USA), α,α -azobisisobutyronitrile (AIBN, Kanto Chemical Co., Inc., Tokyo, Japan) and t-butyl acrylate.…”

Cell–Material Interactions 2022

“…Biological evaluations, especially concerning the toxicity, were the topic of potentially respirable polyacrylamides [ 7 , 8 ], as well as caffeine–cyclodextrin host–guest complexes [ 9 ]. The studies on polyacrylamides highlight that organic compounds may also cause pulmonary fibrosis with long-term effects and that polymer structural features such as molar mass or crosslinking might contribute to the overall toxic effect.…”