Pulmonary toxicity induced by intratracheal instillation of Asian yellow dust (Kosa) in mice

Asian yellow dust (Kosa) causes adverse respiratory health effects in humans. The objective of this study was to clarify the lung toxicity of Kosa. ICR mice (5 weeks of age) were administered intratracheally with Kosa samples-two samples from Maowusu desert and Shapotou desert, one sample consisted of Shapotou Kosa plus sulfate, and natural Asian dust (NAD) from the atmosphere of Beijing-at doses of 0.05, 0.10 or 0.20 mg/mouse at four weekly intervals. The four Kosa samples tested had similar compositions of minerals and concentrations of elements. Instillation of dust particles caused bronchitis and alveolitis in treated mice. The magnitude of inflammation was much greater in NAD-treated mice than in the other particles tested. Increased neutrophils, lymphocytes or eosinophils in bronchoalveolar lavage fluids (BALF) of treated mice were dose dependent. The number of neutrophils in BALF at the 0.2 mg level was parallel to the content of β-glucan in each particle. The numbers of lymphocytes and eosinophils in BALF at the 0.2 mg level were parallel to the concentration of SO42− in each particle. Pro-inflammatory mediators-such as interleukin (IL)-12, tumor necrosis factor-(TNF)-α, keratinocyte chemoattractant (KC), monocyte chemotactic protein (MCP)-l and macrophage inflammatory protein-(MIP)-lα in BALF-were greater in the treated mice. Specifically, NAD considerably increased pro-inflammatory mediators at a 0.2 mg dose. The increased amounts of MlP-lα and TNF-α at 0.2 mg dose corresponded to the amount of β-glucan in each particle. The amounts of MCP-l or IL-12 corresponded to the concentration of sulfate (SO42−) at a 0.2 mg dose. These results suggest that inflammatory lung injury was mediated by β-glucan or SO42−, which was adsorbed into the particles, via the expression of these pro-inflammatory mediators. The results also suggest that the variations in the magnitude of inflammation of the tested Kosa samples depend on the amounts of these toxic materials.