牛磺酸减轻碘海醇诱导的人肾小管上皮细胞损伤

Taurine attenuates cytotoxicity induced by iohexol .in human renal tubular epithelial cells

目的 探讨牛磺酸能否减轻碘海醇导致的HK-2细胞（人近端肾小管上皮细胞）损伤及作用机制.方法 不同碘浓度（25、50、100、125 gI/L）的碘海醇作用HK-2细胞6h;碘浓度为100 gI/L的碘海醇作用HK-2细胞不同时间（2 h、4 h、6 h）,观察细胞损伤程度.选用碘海醇（100 gI/L、6 h）作为刺激组,用不同浓度牛磺酸（3、12、24 mmol/L）共孵育进行干预.细胞增殖-毒性试剂盒（CCK-8）测定细胞活力.Hoechst33342染色、荧光显微镜下观察细胞凋亡形态.流式Annexin V-FITC-PI双染和半胱氨酸天冬氨酸蛋白酶（caspase-3）活性比色法观察细胞凋亡.Western印迹检测Bcl-2、Bax的表达.流式DCFH-DA细胞内标记法测定细胞内活性氧（ROS）.结果 碘海醇呈碘浓度和时间依赖性诱导HK-2细胞活力下降、凋亡增加（P＜0.05）.碘海醇（100 gI/L、6 h）导致HK-2细胞ROS升高（P＜0.05）.牛磺酸呈浓度依赖性增加HK-2细胞活力,减轻凋亡.牛磺酸（3、12、24 mmol/L）干预组与碘海醇刺激组比较,细胞活力分别为（88.0±1.00）%、（91.33±0.58）%、（95.67±1.52）%比（76.67±1.53）%（均P＜0.05）;细胞凋亡率分别为（8.84：±1.75）%、（7.86±1.82）%、（6.30±1.50）%比（11.98±0.39）%（均P＜0.05）;caspase-3的活性分别为（1.33±0.10）、（1.27±0.0）、（1.10±0.04）比（1.42±0.1）（均P＜0.05）.牛磺酸上调HK-2细胞Bcl-2表达,降低了细胞内ROS的升高（均P＜0.05）.结论 碘海醇可致HK-2细胞凋亡增加.氧化应激参与了HK-2细胞损伤.牛磺酸通过减轻细胞内氧化应激、促进Bcl-2表达上调,减轻碘海醇诱导的HK-2细胞凋亡和损伤.

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