Microcystin-LR induces lung injury in mice through the NF-κB/NLRP3 pathway.

Microcystin-LR (MC-LR) a cyclic toxin produced by cyanobacterial species is known to exert detrimental effects on various organs, including lung. Several investigators demonstrated that MC-LR exerts pulmonary toxicity, but the underlying mechanisms remain unclear. This study aimed to investigate whether exposure to MC-LR-induced lung inflammation and examine the underlying mechanisms. Thirty specific pathogen-free (SPF) male mice were allocated into control and MC-LR treatment groups. Mice were intraperitoneally injected with physiological saline or MC-LR (20 μg/kg) daily for a total of 21 days. Our findings indicated that exposure to MC-LR-produced histopathological changes in lung tissue, including thickening of alveolar walls and inflammatory infiltration. MC-LR was found to upregulate mRNA expression levels of pro-inflammatory cytokines TNFα, IL-6, IL-1β, and IL-18. Further, MC-LR significantly elevated the expression levels of proteins associated with the NF-κB/NLRP3 pathway p-NF-κB, NLRP3, Caspase-1, ASC. The activation of NF-κB/NLRP3 pathway further promoted the release of inflammatory cytokine IL-1β and cleavage of pyroptosis-associated GSDMD protein. These findings indicate that MC-LR may induce lung inflammation by promoting cell pyroptosis via the activation of the NF-κB/NLRP3 pathway.