造影剂激活p38信号通路诱导肾小管细胞凋亡

Contrast media induced apoptosis in renal tubular cells via the activation of p38 mitogen-activated protein kinase

目的探讨丝裂素激活蛋白激酶(MAPK)信号通路在造影剂诱导的肾小管细胞凋亡中的作用。方法培养大鼠肾小管细胞(NRK-52E),分别加入不同种类和浓度的造影剂刺激,部分实验同时加入SB203580(p38MAPK抑制剂)。台盼蓝排除试验检测细胞膜完整性。流式细胞仪DNA分析、FITC-AnnexinⅤbinding/PI染色以及电镜扫描检测细胞凋亡。Western印迹分析和免疫沉淀法检测MAPK的磷酸化水平和活性。结果高渗性造影剂泛影葡胺可诱导NRK-52E细胞凋亡,并且,在一定的渗透浓度范围内,随着渗透浓度的升高,细胞凋亡率越高;在一定的时间范围内,随着时间的延长,细胞凋亡率也越高。低渗性造影剂欧乃派克在实验浓度范围内则不能诱导NRK-52E细胞凋亡。泛影葡胺刺激NRK-52E细胞15min后,p38MAPK磷酸化水平及活性便明显增加,并持续至60min,120min时磷酸化水平及活性明显降低,几乎回到零水平。总的p38MAPK水平在整个实验期间内几乎无变化。SB203580可明显抑制泛影葡胺诱导的NRK-52E细胞凋亡。p44/p42MAPK的磷酸化水平在整个实验阶段则无明显变化。结论造影剂呈渗透浓度和时间依赖性诱导NRK-52E细胞凋亡,造影剂诱导细胞凋亡与其高渗有关。p38MAPK信号通路的激活介导了造影剂诱导的NRK-52E细胞凋亡。

Objective To investigate whether the effect of contrast media on renal tubular cell apoptosis is mediated via mitogen activated protein kinase(MAPK) activation. Methods NRK 52E cells were incubated in cell culture media[+1%fatel calf serum (FCS)] containing buffer (control) or increasing concentrations of diatrizoate or iohexol for various time periods. In separate experiments, NRK 52E cells were incubated with diatrizoate in the presence of 10 or 20 μmol/L SB203580, an inhibitor of p38 MAPK, for 4 h. Cell membrane integrity was assessed by trypan blue exclusion experiment. Apoptosis was assessed by flow cytometric DNA analysis, FITC Annexin Ⅴbinding/PI staining and electron microscopy. MAPK activity and phosphorylation was evaluated by immunoprecipitation and Western blot analysis. Results Diatrizoate, a kind of hyperosmolal contrast media, induced apoptosis in cultured NRK 52E cells in an osmotic pressure and duration dependent manner. Iohexol, another kind of less hyperosmolal contrast media, could not induce NRK 52E cells apoptosis. In NRK 52E cells incubated with diatrizoate, the level of p38 MAPK phosphorylation and activity increased after 15 min, and remained elevated even at 1 h. In contrast, the level of total p38 protein was not changed in whole experimental period. SB203580 significantly inhibited apoptosis in NRK 52E cells incubated with diatrizoate. The level of p44/p42 MAPK phosphorylation was not changed in whole experimental period. Conclusions Contrast media induces apoptosis in cultured NRK 52E cells in an osmotic pressure and duration dependent manner, which is related to the hypertonicity of contrast media. Contrast media induces apoptosis in NRK 52E cells via activation of p38 MAPK.