Objective To investigate the inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine A (CsA)-induced chronic nephrotoxicity.Methods Four groups of rats with CsA-induced chronic nephrotoxicity were respectively treated with vehicle olive oil, tea polyphenols, CsA and tea polyphenols plus CsA. At the end of the 28th day of treatment, 24 hours urine and blood samples were obtained, and the animals were then sacrificed. The serum and urine samples were analysed for creatinine clearance, and kidney tissue was used for pathologic analysis of renal tubular injury and interstitial fibrosis. The TUNEL assay, apoptosis-related enzyme caspase-3 mRNA detected by RT-PCR, and its enzymatic activity were analysed for the possible detections of cell apoptosis.Results CsA-treated rats displayed increased apoptosis of the tubular and interstitial cells, in comparison with vehicle-treated controls (18. 3±4. 6 vs 4. 8±1.3 cells/mm2, P < 0. 05 ) . In comparision with a Objective To investigate the inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine A (CsA) -induced chronic nephrotoxicity. Methods Four groups of rats with CsA-induced chronic nephrotoxicity were were treated with vehicle olive oil, tea polyphenols , CsA and tea polyphenols plus CsA. At the end of the 28th day of treatment, 24 hours urine and blood samples were obtained, and the animals were then sacrificed. The serum and urine samples were dissected for creatinine clearance, and kidney tissue was used The pathology analysis of renal tubular injury and interstitial fibrosis. The TUNEL assay, apoptosis-related enzyme caspase-3 mRNA detected by RT-PCR, and its enzymatic activity were analysed for the possible detections of cell apoptosis. Results CsA-treated rats showed increased apoptosis of the tubular and interstitial cells, in comparison with vehicle-treated controls (18.3 ± 4.6 vs 4. 8 ± 1.3 cells / mm 2, P <0.05). In comparision with a