Detection of intracellular lamellar bodies as a screening marker for fibrotic lesions

Highlights: • The use of disinfectants is rapidly increasing to block spreading of coronavirus. • We identified a screening marker for disinfectants that can induce fibrotic lesions. • Lamellar body-like structures were notably formed in the disinfectant-treated cells. • Cleavage of the nuclear matrix and damage of mitochondrial structures were observed. • Disinfectants should be introduced into the market under thorough verification on the safety. With the rapid increase in application of disinfectants worldwide as a method to block the spread of coronavirus, many new products are being introduced into the market without thorough verification of their impacts on human health and the environment. In the present study, we aimed to propose a screening marker for materials that can induce fibrotic lung disease using disinfectants, which had been demonstrated as causative materials of chronic inflammation and interstitial fibrosis. We first calculated the corresponding LC₅₀ level based on results from cell viability test and exposed the LC₅₀ level of disinfectants to human bronchial epithelial cells for 24 h. Formation of lamellar body-like structures, cleavage of the nuclear matrix, structural damage of mitochondria were found in the cytosol of the treated cells. We also dosed disinfectants by pharyngeal aspiration to mice to determine the LD0 level. The mice were sacrificed on Day 14 after a single dosing, and lamellar body-like structures were observed in the lung tissue of mice. Herein, we hypothesize that DNA damage and metabolic disturbance may play central roles in disinfectant-induced adverse health effects. Additionally, we propose that formation of lamellar bodies can be a screening marker for interstitial fibrosis.