Size-dependent pyroptosis induction by calcium oxalate monohydrate crystals in HK-2 cells

This article explored the differences in pyroptosis mediated by calcium oxalate monohydrate (COM) crystals with sizes of 100 nm, 1 μm, 3 μm, 5 μm, and 10 μm and were used to induce pyroptosis of HK-2 cells. The proportion of pyroptosis cells was detected by caspase-1/PI double staining. Three small-sized COM crystals (0.1–3 μm) could be endocytosis by HK-2 cells and increased intracellular oxidative stress, which further promoted the activation of NLRP3 inflammasome and pyroptosis. The two COM crystals with large sizes (3–10 μm) were difficult to endocytose, and the main mechanism was the crystal adhesion, leading to pyroptosis. Crystal endocytosis leads to higher pyroptosis. The pyroptosis rates mediated by COM with different sizes were as follows: COM-100nm (17.81%) > COM-1μm (17.28%) > COM-3μm (17.25%) > COM-5μm (12.44%) > COM-10μm (9.05%). The smaller the COM crystal size, the higher the pyroptosis rate, which is related to the stronger oxidative stress.