Objective:To investigate the effect of mycophenolate mofetil(MMF)on proliferation and apoptosis of cyst-lining epithelial cells in patients with autosomal dominant polycystic kidney disease (ADPKD),and to compare its effect with that of rapamycin (RAPA)in vitro.Methods: Primary cultured cyst-lining epithelial cells were treated with MMF and RAPA at different concentrations(0,0.005,0.05,0.5,5 μg/ml)for 48 h or 72 h.The inhibitory effects of them on the cells were evaluated by MTT assay; the cell cycle distribution and apoptotic ratio were determined by flow cytometry.The morphological changes of cyst-lining epithelial cells were observed under transmission electron microscope.Results: Both MMF and RAPA significantly inhibited the proliferation of cyst-lining epithelial cells in a dose- and time-dependent manner.After 48 h treatment,the cells were blocked at S phase by MMF and at G0/G1 phase by RAPA.Both drugs induced cell apoptosis,with the maximal apoptotic rate being (5.53±0.27)% for MMF and (4.36±0.10)% for PAPA.Typical morphological changes of apoptotic cells were observed under electron microscope.Conclusion: MMF can effectively inhibit proliferation and induce apoptosis of cyst-lining epithelial cells,but its inhibitory effect is weaker than that of RAPA.