Objective: To investigate the effect of tea polyphenols on cell apoptosis in rat model of cyclosporine-induced chronic nephrotoxicity.
Methods: Four groups of animals in rat model of cyclosporine-induced chronic nephrotoxicity were respectively treated by olive oil (n = 6), tea polyphenols (TP, n = 6), cyclosporine A (CsA, n = 8) and TP plus CsA (n = 8). At the end of 28th day of treatment, all animals were sacrificed and blood was analyzed for blood serum creatinine and creatinine clearance, kidney tissue for pathologic analysis. The TUNEL assay, caspase-3 mRNA expression detected by reverse transcription-polymerase chain reaction (RT-PCR) and caspase-3 activity were used for the analysis of cell apoptosis.
Results: CsA plus TP ameliorated the CsA-induced decrease of renal function and interstitial fibrosis. There was a significant increase in the number of apoptosis-positive cells in the CsA-vs-CsA plus TP-treated group at four weeks (18.9 +/- 3.3 vs. 7.7 +/- 1.4, P < 0.05). The expression of caspase-3 mRNA and caspase-3 activity of CsA-treated group was significantly higher than that of CsA plus TP-treated group (P < 0.05).
Conclusion: These results indicate that antioxidant tea polyphenols significantly inhibit apoptosis of tubular and interstitial cells in rat model of chronic cyclosporine-induced nephrotoxicity, and suggest that the decrease of cell apoptosis exerted by tea polyphenols may be one of mechanisms to protect renal function and tissue structure.