Research On Biological Activity Of Nano-materials

Because of unique physical chemistry quality and can't be examined by routine methods, Nano-materials exist menace to human health and environment. It is necessary to study the health activities.The dissertation chose three kinds of materials, they were nano-TiO₂ , MWNT, nano-Fe. The dissertation mainly researched on the lung injury. All rats were intratracheally instilled with 10mg/kg bw or 1mg/kg bw of nano-materials. The control group was intratracheally instilled the same volume physiological brine. All rats were intratracheally instilled every three days. At the tenth day, all rats were sacrificed and their lungs were lavaged. The following indexes in bronchoalveolar lavage fluid were examined, (1) amount of leukocyte, (2) activities of LDH, (3) contents of HYP. Lung/body coefficient was measured. At last, did morphological observation and compared change ratio of body weight.Through the experiment we come to the conclusion as follows:1. Body weight increase ratio of nano-TiO₂ -10mg/kg bw group was the lowest. All indexes of nano-10mg/kg bw group were obviously higher than the control group and the nano-1mg/kg bw group (P<0.01 or P<0.05). At the same dose, three indexesof nano-10mg/kg bw group were higher than normal-10mg/kg bw group(P<0.01或P<0.05). The amount of leukocyte was also higher than normal-10mg/kg bw group, but the difference was not statistical significance. The results of morphological observation indicated that the rats in nano-10mg/kg bw group had the heavest injury of lungs.2. The body weight increase ratio of MWNT-10mg/kg bw group was the lowest. Other indexes of MWNT-10mg/kg bw group were obviously higher than the control group and the group of MWNT-1mg/kg bw(P<0.01 or P<0.05). The results of morphological observation indicated that the rats in MWNT 10mg/kg bw group had the heavest injury of lungs.3. The body weight increase ratio of nanosized iron 10mg/kg bw group was lowest. Lung/body coefficient, Leukocyte count and Hydroxyproline(HYP) concentration of nanosized iron 10mg/kg bw group were higher than the control group and the group of nanosized iron 1mg/kg bw(P<0.01 or P<0.05).4. The activitiy of LDH of nano-TiO₂ -10mg/kg bw group was the highest. The content of HYP of MWNT-10mg/kg bw group was the highest. Both groups did injury of lungs, but the injury degree was different.Analyzing the results, gained conclusions as follows:1. Under the same experimental condition, the effect of lung injury was more severity in high-dose nano-TiO₂ than normal TiO₂ and low-dose nano-TiO₂ .2. Under this experimental condition, MWNT had injured lungs. All indexes of high-dose MWNT were higher than low-dose MWNT. MWNT was evaluated to existing latent menace to human health and environment.3. Under this experimental condition, the effect of lung injury is more severity in nano-iron. All indexes of high-dose nano-iron were higher than low-dose nano-iron. Nano-iron existed latent menace to human health and environment.4. At the same dose, three kinds of materials existed notable differences in body weight increase ratio, the activities of LDH and the contents of HYP. It indicated that there were some differences in lung toxicity and action mechanism between different nano-materials.