Toxicity Of Fine Particles To Cells

Cytoxicity of atmospheric fine particles mainly influenced by their size, exposure dose and the substance adsorbed on particulate matters. To study the relationship between cytotoxicity of atmospheric fine particles and the particle dsize, set Hangzhou urban residential as the sampling point, sampled by DLPI rating sampler expetiment a series experiment of fine particulate matters on A549 cells. Due to their nano-characteristics, nano titanium dioxide ?nano TiO₂? are also considered as fine particulate matters. To study the cytoxicity of fine particles comprehensively, we first did experiments to study the cytoxicity of nano TiO₂, to study the relationship between cytoxicity and nano TiO₂ size, to compare the cytoxicity of nano TiO₂ and atmospheric fine particles of different size.Exposed to the same concentration, the smaller of nano TiO₂ size, the smaller the cell activity, the greater the cells members damaged. Fine particles also exposed the cells got the same results, and nano TiO₂ and fine particles of the preferred toxic concentration of cells ?cells showed the lowest concentration of a strong toxicity? were 10?g/mL. Nano TiO₂ can hardly dissolve in water, fine particles also have a part that can not dissolve in water. When exposed to concentrations above 10?g/mL, cell activity changed little, may probably because their solubility in DMEM.Under the optimum exposure concentration, we study the c cellular oxidative stress, found that intracellular ROS activity increased with the decrease of nano TiO₂ particle size, the GSH levels and SOD levels were positively correlated with the particle size. Fine particulates instead of nano TiO₂ also got the same test rule. The smaller the particle size, the smaller the cell activity, the degree of oxidative damage to cells are stronger, showed higher ROS activity. SOD and GSH can inhibit cell oxidative damage, when cellular oxidative damage increased, their activity decreased.RT-PCR to test the expression of apoptotic genes mRNA, 10?g/mL as the exposure concentration, found that with the increasing of particle size, P53, BCL-2 and BAX relative expression levels decreased. Nano TiO₂ and fine particles have the same trend. This shows that the relationship between the expression of the apoptosis gene and particle size are negative correlation, the smaller the particle size, the greater the expression of apoptosis genes.Compared the cytoxicity of nano TiO₂ and airborne fine particulate matters, we found that although the size of the nano TiO₂ and atmospheric fine particles are different, they showed the same cell toxicity trend. Within the size of fine particulate matters, the cytotoxicity of A549 cells greatly influenced by particle size, the smaller the particle size, the greater cytotoxicity. Compare the cytoxity between fine particle and nano TiO₂, we foung that even when the size of fine particles bigger than nano TiO₂, the cell injury, cell oxidative stress and the expression of apoptotic are higher. This indicate that fine particles caused cytoxicity are complex.