Objective    To investigate the possible injury mechanism of human kidney proximal tubular epithelial cell-2 (HK-2) induced by aristolochic acid (AA).     Methods     Cultured HK-2 cells were divided into 4 groups: normal control

treated by AA at the concentration of 30

60 and 120 μmol/L for 48 h respectively. The morphological changes were observed by inverted phase contract microscopy. The cell viability was measured by the Cell Counting Kit-8 (CCK8) assay. Apoptotic cells were identified by flow cytometry. Expression of active Caspase-3 was measured by Western blot analysis. Automatic biochemical analyzer was used to detect the contents of LDH and β-N-Acetylglucosaminidase (NAG) in the supernatant. The expression of E-cadherin and a-SMA was detected with laser scanning confocal microscope (LSCM). Enzyme linked immunosorbent assay (ELISA) was used to measure the levels of TGF-β1 and collagen Ⅲ in the supernatant quantitatively.     Results    AA inhibited HK-2 cells proliferation

induced cell apoptosis and activated Caspase-3 expression

and increased the LDH and NAG levels. All of these were in a concentration-dependent manner. AA at the concentration of 60 μmol/L inhibited E-cadherin expression

increased α-SMA expression and TGF-β1 and collagen Ⅲ secretion.     Conclusion    AA inhibits cell proliferation

induces apoptosis and epithelial-mesenchymal transition (EMT) in HK-2 cells. AA at relatively low concentration (≤60 μmol/L) mainly induces EMT in HK-2 cells

while

that at high concentration (≥120 μmol/L) causes apoptosis and cytotoxicity.