[Inhalation toxicity assessment of silicon dioxide particles in Calu3 cells at the air-liquid interface]

Objective: To establish the air-liquid interface cell exposure (ALICE) model of human bronchial epithelial cells (Calu3 cells) , evaluate the toxic effects of silicon dioxide (SiO(2)) particles on airway epithelial cells, and construct a representative in vitro inhalation exposure toxicity evaluation model for dust. Methods: In January 2025, SiO(2) particles were exposed using the cloud exposure system to establish the Calu3 cells ALICE model. The experimental groups were classified into control group, low dose SiO(2) group (1 μg/cm(2)) , medium dose SiO(2) group (5 μg/cm(2)) , and high dose SiO(2) group (10 μg/cm(2)) . Calu3 cells were seeded in 12-well Transwell chambers and exposed for 24, 48, and 72 hours. Cell viability was detected by CCK-8, and lactate dehydrogenase (LDH) activity was measured by LDH cytotoxicity assay. The concentrations of inflammatory factors interleukin-1β (IL-1β) , interleukin-6 (IL-6) , interleukin-8 (IL-8) , and monocyte chemoattractant protein-1 (MCP-1) were detected by enzyme-linked immunosorbent assay (ELISA) . The expression of zona occludens-1 (ZO-1) , E-Cadherin, and mucin 5AC (MUC5AC) was observed by immunofluorescence double labeling. A one-way analysis of variance (ANOVA) was employed for comparisons among multiple groups, followed by the least significant difference (LSD) test for pairwise comparisons. Results: Compared with the control group, the cell survival rates in the low, medium, and high dose groups, declined following a 24 hours exposure to SiO(2) particles, and the differences were statistically significant (P<0.05) . Compared with the control group, the LDH activity in the low dose group increased after 24, 48, and 72 hours of exposure, and the differences were statistically significant (P<0.05) . Compared with the control group, the transepithelial electrical resistance (TEER) values in the low, medium, and high dose groups [respectively (753.3±55.4) , (595.3±55.0) , and (625.7±43.8) Ω·cm(2)] decreased, and the differences were statistically significant (P<0.01) . Compared with the control group, the expression of IL-1β and IL-6 increased in the low dose group, and the expression of IL-8 and MCP-1 increased in the low and medium dose groups, and the differences were statistically significant (P<0.01) . Immunofluorescence detection indicated that the fluorescence signals of ZO-1 and E-Cadherin on the cell membrane were weakened, the integrity of the cell membrane was compromised, and the fluorescence intensity of MUC5AC increased. Conclusion: Low dose SiO(2) particle exposure can induce structural and functional damage in Calu3 cells, thereby affecting the normal mucus clearance and defense mechanisms of respiratory epithelial cells.