Palmer R J, Butenhoff J L, Stevens J B
Environ Res. 1987 Jun;43(1):142-56. doi: 10.1016/s0013-9351(87)80066-x.
The rare earth metals cerium, lanthanum, and neodymium each were evaluated in an in vitro cytotoxicity assay system using adult, male Sprague-Dawley rat pulmonary alveolar macrophages. Both the soluble chloride form of these metals and their insoluble metal oxides were studied. For comparison purposes, the cytotoxicities of cadmium chloride and cadmium oxide were also quantified in this test system. In general, regardless of the cytotoxicity parameter measured, i.e., cell viability, lysosomal enzyme leakage, or changes in cell surface morphology, cadmium was more toxic to these cells than were the rare earth metals. Of the rare earth metals studied, only lanthanum chloride (LC50 = 52 microM), cerium chloride (LC50 = 29 microM), and neodymium oxide (LC50 = 101 microM) displayed significant cytotoxicity in this test system. Cadmium chloride exhibited an LC50 value of 28 microM, whereas the LC50 value for cadmium oxide was found to be 15 microM. These findings suggest that rare earth metal fumes should be considered as cytotoxic to lung tissue and therefore potentially fibrogenic.
使用成年雄性斯普拉格 - 道利大鼠肺泡巨噬细胞，在体外细胞毒性测定系统中对稀土金属铈、镧和钕分别进行了评估。研究了这些金属的可溶性氯化物形式及其不溶性金属氧化物。为了进行比较，在该测试系统中还对氯化镉和氧化镉的细胞毒性进行了定量。总体而言，无论测量的细胞毒性参数如何，即细胞活力、溶酶体酶泄漏或细胞表面形态变化，镉对这些细胞的毒性都比稀土金属更大。在所研究的稀土金属中，只有氯化镧（LC50 = 52微摩尔）、氯化铈（LC50 = 29微摩尔）和氧化钕（LC50 = 101微摩尔）在该测试系统中表现出显著的细胞毒性。氯化镉的LC50值为28微摩尔，而氧化镉的LC50值为15微摩尔。这些发现表明，稀土金属烟雾应被视为对肺组织具有细胞毒性，因此可能具有致纤维化作用。
