RESUMO
Objective To investigate the protective effect and mechanism of taurine on the cytotoxicity of iohexol on HK-2 cells. Methods HK-2 cells were exposed to iohexol at different dosage (25, 50, 100, 125 gI/L) for 6 h and at the dose of 100 gl/L for different time(2 h, 4 h, 6 h). Then taurine (3,12,24 mmol/L) was coincubated with iohexol (100 gI/L) for 6 h.Cell viability was assessed by CCK-8 assay. Cell apoptosis was determined by Hoechest 33342 flurescence stains,flow cytometry with Annexin V-FITC/PI double stains and caspase-3 activity by colorimetric assay. Bcl-2 and Bax expression were examined by Western blot. Intracellular ROS was detected by flow cytometry with fluorescent probe DCFH-DA. Results Iohexol decreased HK-2 cell viability and induced apoptosis in concentration-dependant and time-dependant manner (all P＜0.05). ROS was increased following iohexol (100 gI/L for 6 h) treatment (P＜0.05). Taurine increased cell viability and attenuated apoptosis in dose-dependant manner. The cell viability levels in taurine intervention (3,12,24 mmol/L) group were significantly increased compared with that in iohexol treated group respectively [(88.00±1.00)%, (91.33±0.58)%, (95.67±1.52) % vs (76.67±1.53)%, all P＜0.05]. Apoptosis rate by flow cytometry were decreased respectively [(8.84±1.75)%,(7.86±1.82)%, (6.30±1.50)% vs (11.98±0.39)%, all P＜0.05]. Caspase-3 activities were decreased respectively [(1.33±0.10), (1.27±0.06), (1.10±0.04) vs (1.42±0.13), all P＜0.05].Taurine up-regulated the expression of Bcl-2, and decreased the intracellular ROS (all P＜0.05).Conclusions Iohexol induces cell apoptosis and oxidative stress. Taurine attenuates direct cytotoxic effect induced by iohexol. The anti-oxidative stress effect and up-regulated Bcl-2 expression may partly account for the protection of taurine.