Effects of AA on mRNA expressions of collagen I, collagen III, collagen IV and α-SMA in rat kidney-derived cell lines. RNAs were extracted from NRK52E or NRK49F cells treated with 5 μM AA and/or 20 μM Ki16425 for 65 h. mRNAs encoding collagen I, collagen III, collagen IV and α-SMA were quantified by real-time RT-PCR. Results are means ± S.E. (NRK52E; n = 6, NRK49F; n = 4). *p < 0.05 compared to the cells treated with vehicle.