Yang Xiao-Gai, Yang Xiao-Da, Yuan Lan, Wang Kui, Crans Debbie C
Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100083, China.
Pharm Res. 2004 Jun;21(6):1026-33. doi: 10.1023/b:pham.0000029293.89113.d5.
The aim of this study was to investigate the mechanism of permeation and cytotoxicity of vanadium compounds, [VO(acac)2], [VO(ma)2], and vanadate.
Absorptive transport were carried out in Caco-2 monolayers grown on transwell inserts. Vanadium was quantified using inductively coupled plasma atomic emission spectrometry (ICP-AES). The change of Caco-2 cells in the microvilli morphology and F-actin structure was visualized by transmission electron microscopy and confocal laser scanning microscopy.
The three vanadium compounds were taken up by Caco-2 cells via simple passive diffusion. [VO(acac)2] were mainly transcellularly transported and exhibited the highest apparent permeabilty coefficients (8.2 x 10(-6) cm(-1)). The cell accumulation of [VO(acac)2] was found to be greater than that of [VO(ma)2], and vanadate caused much less accumulation than the other two compounds. Vanadium compounds induced intracellular reactive oxygen species, reduced the transepithelial electric resistance, caused morphological change in microvilli, and led to different perturbation of F-actin structure.
The three compounds exhibited different permeability due to different diffusion process and cellular uptake. The toxicity of vanadium complexes on Caco-2 monolayer involved F-actin-related change of tight junction and impairment of microvilli. The toxicity was also related to elevated intracellular reactive oxygen species (ROS) and their cellular accumulation.
本研究旨在探究钒化合物[VO(acac)2]、[VO(ma)2]和钒酸盐的渗透机制及细胞毒性。
在Transwell小室上生长的Caco-2单层细胞中进行吸收转运实验。使用电感耦合等离子体原子发射光谱法（ICP-AES）对钒进行定量分析。通过透射电子显微镜和共聚焦激光扫描显微镜观察Caco-2细胞微绒毛形态和F-肌动蛋白结构的变化。
三种钒化合物通过简单的被动扩散被Caco-2细胞摄取。[VO(acac)2]主要通过细胞转运，表现出最高的表观渗透系数（8.2×10(-6) cm(-1)）。发现[VO(acac)2]的细胞蓄积量大于[VO(ma)2]，且钒酸盐引起的蓄积量比其他两种化合物少得多。钒化合物诱导细胞内活性氧生成，降低跨上皮电阻，引起微绒毛形态变化，并导致F-肌动蛋白结构的不同扰动。
三种化合物由于不同的扩散过程和细胞摄取而表现出不同的渗透性。钒配合物对Caco-2单层的毒性涉及紧密连接的F-肌动蛋白相关变化和微绒毛损伤。毒性还与细胞内活性氧（ROS）水平升高及其细胞蓄积有关。
