title: [Aristolochic acid induced transdifferentiation and apoptosis in human tubular epithelial cells in vitro].
abstract: OBJECTIVE
  To examine the possible role of aristolochic acid (AA) in transdifferentiation and apoptisis of human tubular epithelial cell line (HKC).
  
  
  METHODS
  Cultured HKC cells were divided into five groups: serum-free (negative control) and treatment with AA at the concentrations of 5 mg/L, 10 mg/L, 20 mg/L and 40 mg/L for 48 hours, respectively. Transdifferentiation of HKC cells was observed with the following methods: detection of the expression of vimentin and cytokeratin of HKC cells with indirect immunoflourescence, determination of expression of E-cadherin and alpha-smooth muscle actin (alpha-SMA) by indirect immunohistochemical double staining, and determination of the proportion of alpha-SMA (+) HKC cells by flow cytometry. The apoptosis of HKC cells was observed with Giemsa staining, TUNEL reaction and agarose gel electrophoresis, and the ratio of apoptotic HKC cells was quantitatively analyzed by flow cytometry with propidium iodide staining.
  
  
  RESULTS
  The expression of cytokeratin and E-cadherin reduced and that of vimentin increased in HKC cells treated with 10 mg/L of AA for 48 hours, and the expression of alpha-SMA (+) in HKC cells treated with 10 mg/L of AA (14.17 +/- 0.61)% was significantly higher than that in serum-free controls (3.57 +/- 0.52)%. Apoptosis of HKC cell treated with 40 mg/L of AA for 48 hours was 53.4%, significantly higher than that in serum-free controls (2%). Treatment with 5 mg/L of AA and 20 mg/L of AA could not induce apoptosis and transdifferentiation of cells.
  
  
  CONCLUSIONS
  Treatment with relatively low concentration of AA (10 mg/L) might induce slight transdifferentiation in cultured HKC cells and that with higher concentration of AA (40 mg/L) for 48 hours might induce apparent apoptosis of these cells, which suggested that transdifferentiation and apoptosis of tubular epithelial cells probably played important roles in aristolochic acid-induced nephropathy.
authors.affiliation: Division of Nephrology, Peking Union Medical Collage Hospital, Beijing 100730, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Su
authors.forename: Shaowei
authors.initials: S
authors.lastname: Xu
authors.forename: Falei
authors.initials: F
authors.lastname: Zheng
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000199:Actins / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D034341:Aristolochic Acids / Q000494:pharmacology*; D002273:Carcinogens / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D053938:DNA Fragmentation / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007684:Kidney Tubules / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D008854:Microscopy, Electron; D009130:Muscle, Smooth / Q000737:chemistry
chemical_list: D000199:Actins; D034341:Aristolochic Acids; D002273:Carcinogens; C000228:aristolochic acid I