86 Indoor dust-induced cytotoxicity in dynamic lung-on-chip: role of exposure duration and mechanical cues

Abstract Humans are daily exposed to a variety of chemicals and particulate matter that accumulate in indoor dust (ID). Lung in vitro models offer the opportunity to study the effects of inhaled ID. However, most fail to address the influence of breathing motion on the observed effects. This work evaluates the effect of ID on the AX12C iAlv lung-on-chip model with breathing motion ability, following acute and long-term repeated exposure. The model consists of primary cell-derived immortalized alveolar epithelial cells (AXiAECs) seeded on the AX12 platform. NIST standard reference materials 2,583 and 2,585 were tested under submerged conditions. Acute exposure studies included exposing the model to 5 and 33 μg/cm2 and incubating for 24 h in static conditions or under three-dimensional cyclic stretch, mimicking the human breathing motion. Long-term exposure studies compared a 5-time repeated cumulative exposure, reaching 5 µg/cm2 by day 5, with a single exposure to 5 µg/cm2 at day 5, inquired after 72 h. Endpoints included transepithelial electrical resistance, metabolic activity, paracellular transport of lucifer yellow, and lactate dehydrogenase release. ID exposure under cyclic stretching conditions resulted in a stronger cytotoxic effect, disrupting barrier function without compromising cell viability. Additionally, a single 72 h exposure to ID induced a more pronounced cytotoxic effect compared to repeated cumulative exposure. Our findings underscore the importance of exposure duration and mechanical cues in evaluating cellular responses to ID. Undergoing work includes cytokine profiling and RT-qPCR of cytotoxic markers. Additionally, the effects of cyclic stretching in long-term repeated exposure will be evaluated.