title: High Concentration of Calcium Stimulates Calcium Oxalate Crystal Attachment to Rat Tubular Epithelial NRK Cells Through Osteopontin.
abstract: OBJECTIVE
  To address whether hypercalciuria can stimulate calcium oxalate (CaOx) crystal deposition in kidney through osteopontin (OPN).
  
  
  METHODS
  Rat tubular epithelial NRK cells were exposed to calcium. The cell viability, the cellular malondialdehyde content as a marker of reactive oxygen species (ROS), and the release of lactate dehydrogenase as markers of injury were detected. The production and gene expression of OPN were also examined. CaOx crystal attachment to cells was accomplished by measuring the calcium concentration of the cell lysates with atomic absorption analysis.
  
  
  RESULTS
  Exposure to calcium produced signs of cell injury and ROS-induced lipid peroxidation. The messenger ribonucleic acid expression and production of OPN increased significantly. OPN knockdown can significantly decrease the amount of CaOx crystal attachment to NRK cells.
  
  
  CONCLUSIONS
  In response to exposure to high concentration of calcium, renal tubular epithelial NRK cells increase the production of OPN, which may have a promoting role in CaOx crystal adhesion to NRK cells by calcium stimulation.
authors.affiliation: The Department of Urology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, People's Republic of China.
authors.forename: Qilin
authors.initials: Q
authors.lastname: Xi
authors.affiliation: The Department of Urology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ouyang
authors.affiliation: The Department of Urology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, People's Republic of China.
authors.forename: Jinxian
authors.initials: J
authors.lastname: Pu
authors.affiliation: The Department of Urology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, People's Republic of China. Electronic address: xf192@163.com.
authors.forename: Jianquan
authors.initials: J
authors.lastname: Hou
authors.affiliation: The Department of Urology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China.
authors.forename: Shaogang
authors.initials: S
authors.lastname: Wang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002129:Calcium Oxalate / Q000378:metabolism*; D002478:Cells, Cultured; D003460:Crystallization; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation; D053565:Hypercalciuria / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D007684:Kidney Tubules / Q000378:metabolism* / Q000473:pathology; D053495:Osteopontin / Q000096:biosynthesis / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics*; D051381:Rats
chemical_list: D053495:Osteopontin; D002129:Calcium Oxalate; D012313:RNA; D002118:Calcium