Host: The Japanese Society of Toxicology
Name : The 47th Annual Meeting of the Japanese Society of Toxicology
Date : 2020 -
In order to accelerate the social implementation of cellulose nanofibers (CNFs), which are expected to be used in a variety of new materials, it is necessary to evaluate the safety of CNFs. However, there is still little information on the effects of inhalation. In this presentation, after examining the following (1) to (3), we conducted a rat intratracheal instillation test to elucidate the inhalation effect of chemically modified CNFs, compared with multi-walled carbon nanotubes (MWCNTs) (4). (1) CNFs have an intermediate property between gel and sol, and its viscosity changes with time and shear rate (thixotropy). Therefore, we dispersed and prepared slurry CNFs without damaging the physicochemical properties. (2) After intratracheal instillation, CNF samples may cause suffocation or behavioral abnormalities in rodents because the physico-chemical properties of CNFs. Thereafter, we observed the state of the rat for several days and measured injection state of CNF dispersion from feeding needle. The concentration and administration conditions of the CNF samples that could be intratracheally instilled were established. (3) We prepared CNF stained with a chemical dye and analyzed of CNF in each lobe of rat lungs after intratracheal instillation. We verified that the test material was not unevenly distributed in the lungs after intratracheal instillation and was uniformly distributed. (4) We analyzed the number of cells, total protein, lactate dehydratase activity (LDH), cytokines in bronchoalveolar lavage fluid (BALF), and pathological observation during 90 days of intratracheal instillation of CNF samples, and verified the degree of inflammation and the changes over time. These results suggested that the inflammatory response due to the CNF was weaker than that of MWCNTs and decreased over time. This presentation was based on the results obtained from a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO).
