摘要目的:探讨高浓度游离间接胆红素对大鼠肾小管上皮细胞的损伤及机制。方法:体外培养大鼠肾小管上皮细胞NRK-52E接种贴壁后分为高胆红素组和对照组，高胆红素组加入游离间接胆红素浓缩液，调整游离间接胆红素浓度达到140 nmol/L。孵育培养24 h后观察细胞形态，检测细胞凋亡、细胞凋亡相关基因B淋巴细胞瘤2（B-cell lymphoma-2，Bcl-2）、B淋巴细胞瘤2相关X蛋白（B-cell lymphoma-associated X protein，Bax）和半胱氨酸天冬氨酸特异性蛋白酶3（cysteinyl aspartate specific protease 3，Caspase-3）蛋白表达及细胞内活性氧浓度，观察细胞内线粒体膜通透性转换孔（mitochondrial permeability transition pore，MPTP）开放程度。结果:高胆红素组24 h细胞凋亡数量明显增多，细胞凋亡率高于对照组［（22.21%±0.24%）比（5.35%±0.23%）］，差异有统计学意义（ P<0.001）。与对照组比较，高胆红素组细胞内MPTP开放增加，Bcl-2蛋白表达下降，Bax和Caspase-3蛋白表达升高，差异均有统计学意义（ P<0.05）。高胆红素组细胞内活性氧浓度高于对照组［（27.29%±0.88%）比（4.39%±0.49%）］，差异有统计学意义（ P<0.001）。 结论:高浓度游离间接胆红素可导致大鼠肾小管上皮细胞凋亡，机制可能与高浓度游离间接胆红素促进线粒体内MPTP异常开放、增加细胞内活性氧浓度，抑制Bcl-2蛋白表达、刺激Bax和Caspase-3蛋白表达，最终启动凋亡程序有关。

abstractsObjective:To investigate the effects and mechanism of high-concentration free unconjugated bilirubin on rat renal tubular epithelial cells.Methods:NRK-52E renal tubular epithelial cells from rats were cultured, attached to the wall, and then split into a high bilirubin group and a control group. In the high bilirubin group, a solution with free unconjugated bilirubin was added to adjust the free indirect bilirubin concentration to 140 nmol/L. After 24 h of cell incubation, researchers observed cell morphology, detected apoptosis, measured protein expressions of apoptosis-related genes B-cell lymphoma-2 (Bcl-2), B-cell lymphoma-associated X protein (Bax) and Cysteinyl aspartate specific protease 3 (Caspase-3), assessed were detected, the intracellular reactive oxygen species (ROS) levels, and visualized mitochondrial permeability transition pore (MPTP) opening.Results:At 24 hours, apoptosis increased significantly in the high bilirubin group, compared to the control group [(22.21%±0.24%) vs. (5.35%±0.23%), P<0.001]. Additionally, the high bilirubin group showed increased intracellular MPTP opening, decreased Bcl-2 protein expression, and increased Bax and Caspase-3 protein expressions, with all protein gray value differences being statistically significant ( P<0.05). Intracellular ROS levels were significantly higher in the high bilirubin group compared to the control group [(27.29%±0.88%) vs. (4.39%±0.49%), P<0.001]. Conclusions:High levels of free unconjugated bilirubin can cause apoptosis in rat renal tubular epithelial cells by potentially triggering mitochondrial MPTP opening, increasing ROS, suppressing Bcl-2, and activating Bax and Caspase-3, thus initiating the apoptotic pathway.