石棉纤维间接作用的细胞毒性及遗传毒性

The cytotoxicity and genotoxicity induced by chrysotile asbestos indirectly

目的 探讨石棉纤维与培养的人肺泡上皮细胞间接作用 (纤维不与细胞直接接触 )后的细胞毒性和遗传毒性 ,以及活性氧在其中的作用。方法 用固体作用物与培养细胞隔开的TRANSWELL培养板 ,观察由国际抗癌团体(UICC)提供标准温石棉对人肺泡上皮 (A5 49)细胞间接作用及直接作用不同时间后的细胞毒性和遗传毒性。同时 ,在染毒过程中分别加入活性氧清除剂 [过氧化氢酶 (CAT)、超氧化物歧化酶 (SOD)、甘露醇 (Mannitol) ] ,以观察活性氧在石棉间接作用引起的细胞毒性及遗传毒性中的影响。结果 UICC温石棉纤维直接与A5 49细胞接触 ,作用 2 4h ,在 40 μg ml时可引起细胞存活率明显下降 ,而石棉纤维间接与细胞作用 2 4h ,则在 80 μg ml时才引起细胞存活率的明显下降。在石棉直接作用时 ,3种抗氧化剂均可部分抑制石棉导致的细胞存活率下降 ,但均未抑制到对照组水平 ;而在石棉间接作用时 ,3种抗氧化剂均可完全抑制石棉纤维导致的细胞存活率下降。UICC温石棉纤维直接与A5 49细胞接触 ,作用 2 4h ,在 10μg ml时即可明显引起细胞DNA链断裂 ,而石棉纤维间接与细胞作用 2 4h ,即使在 80 μg ml时也未能引起细胞DNA链断裂程度的明显增加。而当较高浓度的温石棉与A5 49细胞间接作用 3h ,均可引起细胞DNA链断裂的明显增?

Objective To study the cytotoxicity and gentoxicity induced by chrysotile fibers in human alveolar epithelia cells without direct contact to the cells and the role of reactivated oxygen species(ROS) in the toxicity.Methods TRANSWELL culture plates which can separate the solid reagent and cultured cells were used to study the cytoxicity and genotoxicity induced by UICC chrysotile fibers indirectly and directly,the scavengers of ROS such as catalase(CAT),superoxide dismutase(SOD) and mannitol were also used to study the role of ROS in the indirect cytotoxicity and genotoxicity of chrysotile fibers.Results 40 μg/ml of chrysotile fibers can cause cell death significantly when interacted with cells directly for 24 hours,whereas the concentration should be doubled to cause the same effect when chrysotile fibers interacted with cells indirectly.All the antioxidants could alleviate the direct cytotoxicity of chrysotile fibers,however,the antioxidants could inhibit the indirect cytotoxicity of chrysotile fibers completely.10 μg/ml of chrysotile fibers could induce obvious DNA strand breaks when interacted with cells directly for 24 hours,however,this DNA damage could not be found when the cells were cultured with chrysotile fibers indirectly,even the concentration of chrysotile increased to 80 μg/ml.When the cells were cultured with chrysotile fibers indirectly for 3 hours,40 μg/ml and upward concentration of chrysotile fibers could induce DNA damage significantly.All the antioxidants were capable to inhibit the genotoxicity of chrysotile in manner of indirect interaction,mannitol and SOD could inhibit this kind of damage completely.Conclusion Chrysotile fibers were able to damage the target cells by means of ROS generated from its surface even the cells were not contacted with chrysotile directly,and these results can help to control the harm of chrysotile through the surface modification.