title: [Effects of exogenous epidermal growth factor (EGF) on growth inhibition induced by aristolochic acid I (AA-I) in renal proximal tubular epithelial cells].
abstract: OBJECTIVE
  The purpose of this study was to investigate the effects of exogenous epidermal growth factor (EGF) on the growth inhibition of renal proximal tubular epithelial cell induced by AA-I.
  
  
  METHODS
  Cultured human renal proximal tubular epithelial cell line HK-2 was used as the subject. The changes of the survived HK-2 cells were observed and compared among control, AA-I stimulation, pre-EGF, together-EGF and post-EGF groups. In the study, cellular morphologic assessments were performed with a phase-contrast inverted microscope. Cell counting after stained with 0.04% trypan blue was adopted to analyze cell proliferation. Cell cycle was assessed by flow cytometry.
  
  
  RESULTS
  Number of the survived cells stimulated by AA-I for 12, 24, 48 hours decreased gradually in a dose and time dependent manner. At 24, 48 hours, the survived cells showed a significant disturbance in the cell cycle procedure, which was characterized as decreased percentage of cells in G0/G1 phase, significant increased percentage of cells in G2/M phases. Exogenous EGF (20 microg L(-1)) could significantly promote the proliferation of HK-2 cells, which shown a increased cell number, accompanied down-regulated cells in G0/G1 phase, increased cells in S and G2/M phase. Compared with AA-I groups, it failed to improve the inhibitory effect on cell proliferation and abnormal cell cycle procedure by AA-I, no matter EGF was added in before, at same time or after AA-I stimulation.
  
  
  CONCLUSIONS
  AA-I (10 g L(-1)) has remarkable growth inhibition effects on survived RTEC, and can induce a blockage of G2/M phase in the cell cycle procedure. Exogenous EGF (20 microg L(-1)) promote the proliferation in normal cultured HK-2 cell. EGF treatment could not improve the proliferation inhibitory effect induced by AA-I, no matter adding EGF to cultures before, together with AA-I or after AA-I stimulation.
authors.affiliation: Renal Division, Department of Medicine, First Hospital and Institute of Nephrology, Peking University, Beijing 100034, China.
authors.forename: Na
authors.initials: N
authors.lastname: Zhou
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Tang
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Li
mesh_terms: D034341:Aristolochic Acids / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects*; D005434:Flow Cytometry; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000187:drug effects; D009153:Mutagens / Q000494:pharmacology*
chemical_list: D034341:Aristolochic Acids; D009153:Mutagens; D004815:Epidermal Growth Factor; C000228:aristolochic acid I