Caspase-1 mediates the formation and release of PyrBDs in macrophages. (A) Observation of the pyroptosis of alveolar macrophages by microscope. (B) Representative scanning electronic microscopy (SEM) images of alveolar macrophages treated with LPS and Nig. Alveolar macrophages from the WT mice showed swelling, release of cytoplasmic content, plasma membrane bubbles, and adhesion of micron-sized vesicles. In the Casp1-/- group, no similar morphological changes were observed. Bar = 5 μm. (C) Immunoblot analysis for pyroptosis-related proteins, caspase-1 full length (Casp1-FL), cleaved caspase-1, GSDMD full length (GSDMD-FL), GSDMD-N-terminal (GSDMD-N), and IL-1β. Data are expressed as the mean ± SD. (D) Lack of caspase-1 led to a decrease in PyrBDs released by alveolar macrophages. Data are expressed as the mean ± SD, ***P < 0.001.