Souza V, Bucio L, Gutiérrez-Ruiz M C
Universidad Autónoma Metropolitana-Iztapalapa, Laboratorio de Fisiología Celular, Departamento de Ciencias de la Salud, DCBS, México, D.F.
Toxicology. 1997 Jul 11;120(3):215-20. doi: 10.1016/s0300-483x(97)00057-7.
A hepatic human cell line (WRL-68 cells) was employed to investigate the uptake of the toxic heavy metal cadmium. Cd accumulation in WRL-68 cells is a time-, temperature- and concentration-dependent process. A rapid initial phase of uptake was followed by a second slower phase. The transport does not require energy and 55% of Cd transport occurs by temperature-insensitive processes, possibly by diffusion. The rest of Cd transport (45%) occurs by temperature-sensitive processes, probably ion channels and carriers, that involve interaction with sulfhydryl groups. The calcium channel blockers nifedipine and verapamil inhibit the uptake of cadmium, with an inhibition of 35% after 30 min incubation with 100 microM verapamil and 10 microM Cd. These data suggest that about one third of the Cd enters WRL-68 cells through the calcium channels. The toxic metals appear to use the transport pathways that exist for biologically essential metals. Our results in human hepatic cells are very similar to those reported in cultured rat hepatocytes. It appears that transport pathways available for Cd uptake are similar and independent of the species of hepatocyte origin. Moreover, the WRL-68 cell line seems to be an excellent in vitro model to study the mechanism of cell damage due to Cd.
采用一种人肝细胞系（WRL - 68细胞）来研究有毒重金属镉的摄取。WRL - 68细胞中镉的积累是一个时间、温度和浓度依赖性过程。摄取的初始阶段迅速，随后是第二个较慢的阶段。该转运不需要能量，55%的镉转运通过对温度不敏感的过程发生，可能是通过扩散。其余45%的镉转运通过对温度敏感的过程发生，可能是离子通道和载体，这涉及与巯基的相互作用。钙通道阻滞剂硝苯地平和维拉帕米抑制镉的摄取，在与100微摩尔/升维拉帕米和10微摩尔/升镉孵育30分钟后抑制率为35%。这些数据表明约三分之一的镉通过钙通道进入WRL - 68细胞。有毒金属似乎利用了生物必需金属存在的转运途径。我们在人肝细胞中的结果与在培养的大鼠肝细胞中报道的结果非常相似。看来可用于镉摄取的转运途径是相似的，且与肝细胞来源的物种无关。此外，WRL - 68细胞系似乎是研究镉引起细胞损伤机制的一个优秀体外模型。
