Effect of Crystal Size of Calcium Oxalate Dihydrate on Cytotoxicity of African Green Monkey Kidney Epithelial Cells

Cytotoxcity differences of submicron (700 nm) and micron (15 μm) calcium oxalate dihydrate (COD) on African green monkey kidney epithelial (Vero) cells were investigated by scanning electron microscope, laser scanning confocal microscope, inductively coupled plasma emission spectrometer, flow cytometry, microplate reader, cell pro- liferation assay kit and lactate dehydrogenase (LDH) release assay kit. The results revealed that both submicron and micron COD could decrease cell viability, increase LDH release amount, enhance propidium iodide staining, and up-regulate negatively-charged osteopontin expression, which indicated that both submicron and micron COD crystals could damage Vero cells. Submicron COD exhibited higher cytotoxicity and more adhesion amount than micron COD. The higher cytoxicity of submicron COD was discussed from change of crystal face, surface charge, surface adhesion sites, and hydrogen bonding between cells and crystals.