#0150 Pulmonary toxicity of tungsten trioxide nanoparticles in an inhalation study and an intratracheal instillation study
Are Tungsten Trioxide Nanoparticles Toxic to the Lungs?
Nanoscale materials such as nanoparticles have many applications in renewable energy systems, the food industry, health and medicine, high-speed computing, water purification, etc. But, as with other chemical substances, exposure to nanoparticles can be toxic for humans. Hazardous chemicals can cause lasting inflammation in the lungs which eventually leads to lung cancer and pulmonary fibrosis. It is thus important to evaluate the safety of nanoparticles and gauge their potential for toxicity in humans.
A similar line of reasoning led a group of researchers to study the toxicity of tungsten trioxide (WO3) nanoparticles. Despite having a variety of uses and advanced applications in visible-light photocatalysis, household dust removal, or creation of a sterile environment, their toxicity to humans is not fully studied.
To this end, the researchers used two methods for experimentally studying the inflammatory changes induced by WO3 in rat models. The first method involved the introduction of WO3 in rats via an inhalation route, similar to the route of WO3 exposure in humans. The other method involved instillation of WO3 directly in the trachea of rats, which allowed greater control over WO3 dose.
In both studies, two different doses of WO3 corresponding to long-term exposure in workers were studied. Rats inhaling clean air were used as controls for observation. Pulmonary inflammation with exposure to WO3, if any, was examined using lung fluids and tissues samples collected at different timepoints after initiating the study.
The researchers found that even after four weeks of WO3 exposure, pulmonary inflammation among rats was short-lived. Concentration of biomarkers for inflammation and oxidative stress also hinted at mild and low levels of pulmonary inflammation. Furthermore, observation of lung tissues did not reveal any changes with WO3 exposure.
Based on past evidence of persistent inflammation with high toxicity nanoparticles, the researchers suggest that short-lived inflammation with WO3 could well be due to its low toxicity. Moreover, based on the results of the inhalation study, they also propose the level of WO3 nanoparticle exposure that can be safe for humans.
Link to original journal article:
https://academic.oup.com/joh/article/64/1/e12367/7249458
Title of the paper:
Pulmonary toxicity of tungsten trioxide nanoparticles in an inhalation study and an intratracheal instillation study
Authors:
Takashi Marui, Taisuke Tomonaga, Hiroto Izumi, Yukiko Yoshiura, Chinatsu Nishida, Hidenori Higashi, Ke-Yong Wang, Miyako Shijo, Masaru Kubo, Manabu Shimada, and Yasuo Morimoto
