Effects Of Oxidized Multi-walled Carbon Nanotubes On Living Organism And Pregnant Body By Using Radioactive Isotope Trace

In this paper, the oxidized multi-walled carbon nanotubes (oMWCNTs) interaction with nanodiamonds (NDs) and heavy metal pollutions in mice were investigated as well as the damage effects of oMWCNTs on pregnant mice with different pregnancy times by using radioactive isotope trace. In addition, the prevention or treatment drugs for the damages caused by oMWCNTs were also got a preliminary study.i. The results of distribution influence each other between oMWCNTs and NDs in mice through radiolabeling isotope showed that, after a single injectionof oMWCNTs, the highest distribution was found in the lungs, with lower uptake in the liver/spleen; as for NDs injected alone, high distribution in the liver, spleen, and lungs was observed right after. However, uptake in the lungs was decreased obviously after 24 h, while high accumulation in the liver or spleen continued. After co-injection of oMWCNTs and NDs, oMWCNTs significantly affected the distribution pattern of NDs in vivo. Meanwhile, the increasing dose of oMWCNTs decreased the hepatic and splenic accumulation of NDs andgradually increased lung retention. On the contrary, the NDs had no significant effects on the distribution of oMWCNTs in mice. Histological photographs showed that oMWCNTs were mainly captured by lung macrophages,and NDs were located in the bronchi and alveoli after co-administration. oMWCNTs and NDs had different modes of micro-cells. In conclusion, the behavior and fate of NDs in mice depended strongly on oMWCNTs, but NDs had a small influence on the biodistribution and excretion pattern of oMWCNTs.ii. After exposure of oMWCNTs to normal mice.oMWCNTs could not induce the liver to produce metallothionein (MT). When exposing Cd-metallothionein model mouse (Cd-MT mouse) to different doses of oMWCNTs, oMWCNTs could cause Cd2+ release from the accumulated Cd-MT; subsequently, one part of the free Cd2+ was eliminated with blood circulation; the other part adsorbed by oMWCNTs would remain in the tissues together with oMWCNTs.The results of the activities changes of biochemical indexes in plasma and histologyof liver and kidney showed that the hepatotoxicity of co-exposure was lower than that of single exposure, and the hepatotoxicity and accumulation of oMWCNTs in livers depended strongly on the exposure dosage of oMWCNTs. Therefore, the author inferred that MT could be connected with oMWCNTs to reduce their hepatotoxicity, but the detailed mechanism needs to be further studied.iii. The results about the damage effects of oMWCNTs on pregnant mice with different pregnant times showed that oMWCNTscrossed the placental barrier and entered the foetus body. The abortion rates in the pregnant mice depended on pregnancy times.The abortion rates in the first-time, second-time and fourth-time pregnant mice were 70%,40% and 50%, respectively. The maternal body weight gain was inhibited until gestational ages of 13,10 and 11 d. oMWCNTs decreased the serum progesterone level and increased the serum oestradiol level in a dose-and time-dependent manner. However, this effect decreased with gestational age. The histology and vascularendothelial growth factor/reactive oxygen species content in the placenta showed that oMWCNTs narrowed the blood vessel and decreased the number of blood vessels in the placenta.iv. The phospholipid (DOPC) and simvastatin (TD) as the prevention or treatment drugs for the damages caused by oMWCNTs were investigated. The isotope tracing results showed that the presence of DOPC and TD did not affect the distribution of oMWCNTs in mice, while the oMWCNTs had a great influence on the distribution and metabolism of DOPC and TD in mice, because the DOPC and TD had the same distribution as that of oMWCNTs. The biochemical index and histopathology indicated that the DOPC and TD had no obvious prevention effect for the injury of oMWCNTs in mice. However, after exposure TD to the injury mice by the oMWCNTs, the content of the blood urea nitrogen (BUN), cystatin C (Cys-C), alanine aminotransferase(ALT), aspartate aminotransferase (AST), total bilirubin (TB), C-reactive protein (CRP) in serum recovered to normal level, and there were no obvious changes on the histopathology of kidney, spleen and heart, lower pathological changes in lung and liver than that of the control group mice. Therefore, it could be seen that the TD had a good therapeutic effect on the injury caused by oMWCNTs in mice.Through the research of this paper, it could reflect in a certain extent that the biological interaction effect of different nanomaterials or between nanomaterials and heavy metal pollutants in real environment, and provided some data reference for the environmental hazards and cautious emissions of nanoparticle pollutants. The study results of oMWCNTs on the pregnant mice with different pregnancy times could provide theoretical basis for the prevention and treatment of pregnant disorders caused by the atmospheric particulate pollutants. At the same time, the prevention and treatment drugs for the damages caused by oMWCNTs were first investigated, which provided a new thought and breakthrough for the management of nanoparticles environmental hazards.