title: Reinjury risk of nano-calcium oxalate monohydrate and calcium oxalate dihydrate crystals on injured renal epithelial cells: aggravation of crystal adhesion and aggregation.
abstract: BACKGROUND
  Renal epithelial cell injury facilitates crystal adhesion to cell surface and serves as a key step in renal stone formation. However, the effects of cell injury on the adhesion of nano-calcium oxalate crystals and the nano-crystal-induced reinjury risk of injured cells remain unclear.
  
  
  METHODS
  African green monkey renal epithelial (Vero) cells were injured with H2O2 to establish a cell injury model. Cell viability, superoxide dismutase (SOD) activity, malonaldehyde (MDA) content, propidium iodide staining, hematoxylin-eosin staining, reactive oxygen species production, and mitochondrial membrane potential (Δψm) were determined to examine cell injury during adhesion. Changes in the surface structure of H2O2-injured cells were assessed through atomic force microscopy. The altered expression of hyaluronan during adhesion was examined through laser scanning confocal microscopy. The adhesion of nano-calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) crystals to Vero cells was observed through scanning electron microscopy. Nano-COM and COD binding was quantitatively determined through inductively coupled plasma emission spectrometry.
  
  
  RESULTS
  The expression of hyaluronan on the cell surface was increased during wound healing because of Vero cell injury. The structure and function of the cell membrane were also altered by cell injury; thus, nano-crystal adhesion occurred. The ability of nano-COM to adhere to the injured Vero cells was higher than that of nano-COD crystals. The cell viability, SOD activity, and Δψm decreased when nano-crystals attached to the cell surface. By contrast, the MDA content, reactive oxygen species production, and cell death rate increased.
  
  
  CONCLUSIONS
  Cell injury contributes to crystal adhesion to Vero cell surface. The attached nano-COM and COD crystals can aggravate Vero cell injury. As a consequence, crystal adhesion and aggregation are enhanced. These findings provide further insights into kidney stone formation.
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou, People's Republic of China; Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, People's Republic of China.
authors.forename: Qiong-Zhi
authors.initials: QZ
authors.lastname: Gan
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou, People's Republic of China; Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, People's Republic of China.
authors.forename: Xin-Yuan
authors.initials: XY
authors.lastname: Sun
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou, People's Republic of China; Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, People's Republic of China.
authors.forename: Poonam
authors.initials: P
authors.lastname: Bhadja
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou, People's Republic of China; Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, People's Republic of China.
authors.forename: Xiu-Qiong
authors.initials: XQ
authors.lastname: Yao
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou, People's Republic of China; Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, People's Republic of China.
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Ouyang
mesh_terms: D000818:Animals; D002129:Calcium Oxalate / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D003460:Crystallization; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology*; D006820:Hyaluronic Acid / Q000378:metabolism; D007668:Kidney / Q000473:pathology*; D008315:Malondialdehyde / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D013057:Spectrum Analysis; D013194:Staining and Labeling; D013482:Superoxide Dismutase / Q000378:metabolism; D014709:Vero Cells
chemical_list: D017382:Reactive Oxygen Species; D002129:Calcium Oxalate; D008315:Malondialdehyde; D006820:Hyaluronic Acid; D013482:Superoxide Dismutase
keywords: cell injury; crystal adhesion; kidney stones; nano-calcium oxalate crystals