Emodin

The normal rat renal tubular epithelial cell line NRK-52E was purchased from American Type Culture Collection (ATCC, Manassas, United States), and routinely cultured in Dulbecco’s modified Eagle’s medium (DMEM, Wisent, Nanjing, China) containing 10% fetal bovine serum (Gibco, Gaithersburg, MD, United States), 100 U/ml penicillin (Gibco, Carlsbad, CA, United States), and 100 μg/mL streptomycin (Gibco, Carlsbad, CA, United States) at 37°C with 5% CO₂. In the first experiment, NRK-52E cells were pretreated with serum-free medium for 24 h, then exposed to 40 μM or 80 μM emodin (Shanghai Yuanye Bio-Technology Co., Ltd., China) for 24 h. In the second experiment, NRK-52E cells were pretreated with serum-free medium for 24 h, then exposed to 10 ng/mL TGF-β1 (R&D Systems, MN, United States) with or without 40 μM or 80 μM emodin for 24 h. In the third experiment, HEK293 cells were transfected with miR-490-3p mimics, miR-490-3p inhibitors, and negative controls (NCs), then treated with or without 10 ng/mL TGF-β1 for 24 h. In the fouth experiment, NRK-52E cells transfected with miR-490-3p mimics, miR-490-3p inhibitors, and NCs were treated with or without 80 μM emodin for 24 h, then exposed to 10 ng/mL TGF-β1 for 24 h. All control groups were treated with the same volume of vehicle.