Oral Hydroxychloroquine Mitigates Lipopolysaccharide-induced Lung Injury by Inhibiting Pyroptosis in Mice.

Background and objective: Hydroxychloroquine (HCQ) is a molecule derived from quinacrine; it displays a wide range of pharmacological properties, including anti-inflammatory, immunomodulatory, and antineoplastic. However, little is known about this molecule's role in lung injury. This study aimed to identify HCQ's regulatory role of HCQ in sepsis-induced lung injury and its molecular mechanism.

Methods: To test the protective properties of HCQ, we established an in vivo model of lipopolysaccharide (LPS)-induced lung injury in mice. The extent of the injury was determined by evaluating histopathology, inflammatory response, oxidative stress, and apoptosis. Mechanistically, conventional nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing 3 (NLRP3) knockout mice were employed to investigate whether HCQ exerted pulmonary protection by inhibiting NLRP3-mediated pyroptosis.

Results: Our findings revealed that HCQ pretreatment significantly mitigated LPS-induced lung injury in mice in terms of histopathology, inflammatory response, oxidative stress, and apoptosis, while inhibiting LPS-induced NLRP3 inflammasome activation and pyroptosis. Additionally, the indicators of lung injury, including histopathology, inflammatory response, oxidative stress, and apoptosis, were still reduced drastically in LPS-treated NLRP3 (-/-) mice after HCQ pretreatment. Notably, HCQ pretreatment further decreased the levels of pyroptosis indicators, including IL-1β, IL-18 and Cle-GSDMD, in LPS-treated NLRP3 (-/-) mice.

Conclusion: Taken together, HCQ protects against lung injury by inhibiting pyroptosis, maybe not only through the NLRP3 pathway but also through non-NLRP3 pathway; therefore, it may be a new therapeutic strategy in the treatment of lung injury.