nano-TiO_2与1,2,4-TCB联合作用对斑马鱼鳃组织结构及染色体损伤研究

采用组织病理切片法、微核及彗星试验研究nano-TiO_2和1,2,4-TCB联合染毒对斑马鱼鳃组织结构、细胞微核率及DNA损伤的毒性效应。结果表明,单独nano-TiO_2暴露不会导致斑马鱼鳃组织结构损伤,也不会引起明显的微核及染色体损伤。1,2,4-TCB(≥10 mg·L~(-1))会引起鳃组织和细胞染色体的损伤。nano-TiO_2与1,2,4-TCB联合作用会加重斑马鱼的鳃组织结构损伤,出现鳃小片排列严重紊乱,表皮细胞断失严重,鳃小片上皮细胞坏死脱落,鳃丝结构模糊等症状。两者联合作用会引起鳃细胞微核率增加和彗星细胞率的增加,呈现一定的剂量-效应关系,且两者间的联合作用具有协同作用。对彗星试验的尾部DNA百分比、尾长及尾距的分析发现,与对照组和单独作用相比,两者联合作用对彗星指标均有显著增强作用,这表明两者联合作用对染色体的损伤属于非特定片段损伤。

Combined Toxic Effects of Nano Titanium Dioxide (Nano-TiO2) and 1,2,4-Trichlorobenzene (1,2,4-TCB ) on Gill Tissues and Chromosome of Zebrafish

Combined toxicity of nano-TiO2 and 1,2,4-trichlorobenzene (1,2,4-TCB) on zebrafish gills was studied by pathological observation test, micronucleus test and comet assay, using zebrafish and its gill tissues as experimental objects.The results showed that nano-TiO2 did not cause significant structure damage in gill tissues, micronucleus and other chromosome damage.But gill tissues and chromosomes were damaged by 1,2,4-TCB (≥10 mg·L-1).In the combined groups of 1,2,4-TCB and nano-TiO2, the structure damages of gill tissues were aggravated.Serious disorder of the gill lamellae, broken epidermal cells, necrosis of gill epithelial cells and fuzzy structure of gill filaments were observed.The micronucleus percentages and the percentages of comet cells of gill cells were increased with increasing concentrations of nano-TiO2 and 1,2,4-TCB in a dose-effect manner, and the damages caused by nano-TiO2 and 1,2,4-TCB combined treatment showed synergetic effects.The comet indicators of tail DNA percentage, tail length, tail moment of gill cells were all increased significantly in groups treated by mixture of nano-TiO2 and 1,2,4-TCB compared to the control groups, which suggested that the damages of chromosomes of gill cells were not particular piece damage of chromosomes.