Study On Toxicity Of Nano Zinc Oxide In Mice

Nano Zinc Oxide could induce the production of free radicals, cause oxidative damage to the body. At present, results of study on the acute toxicity, chronic toxicity of nano Zinc Oxide are greatly different. This study aims at the acute toxicity, chronic toxicity of nano Zinc Oxide. The results will provide reference for reasonable application of nano Zinc Oxide in the production.Trial 1 Study on the acute injury of nano Zinc Oxide in miceFor detection acute injury of nanometer zinc oxide in mice, nano-ZnO suspension liquid was given to mice through the mouth. The median lethal dose(LD50) was calculated by improved KouShi method. The pathological damage of infected mice was observed after HE staining. Results showed that median lethal dose the nano zinc oxide was 5177 mg/kg·bw, the 95% confidence limits was 5116~5238 mg/kg·bw. High dose of nanometer zinc oxide can result in injury of the mouse small intestine, liver, kidneys, lungs, heart, spleen and other tissues and organs.Trial 2 Study on the subchronic injury of nano Zinc Oxide in miceFor the detection of subchronic injury of nanometer zinc oxide, mice were continuous infected with different doses of nano zinc oxide through intragastric administration. After 90 d, the blood routine index, hepatic function, renal function, anti-oxidation were measured. The pathological damage of liver, kidney and other tissues were observed by HE staining. The results showed that the numbers of red blood cells of 40 mg/kg·bw dose group, 160 mg/kg·bw dose group and 320 mg/kg·bw dose group were significantly lower than the control group(P<0.05); the hemoglobin content of 40 mg/kg·bw dose group was significantly lower than control group(P<0.01). The alanine aminotransferase(ALT) activity of 40 mg/kg·bw dose group was significantly higher than that of control group(P<0.05). The aspartate transaminase(AST) activity of 80 mg/kg·bw dose group and 160 mg/kg·bw dose group was significantly higher than control group(P<0.05). The serum creatinine levels of 80 mg/kg·bw dose group and 160 mg/kg·bw dose group were significantly higher than that of control group(P<0.01). The serum superoxide dismutase(SOD) activity of each infected group was significantly higher than that of control group(P<0.01). The serum hydroxyl free radical inhibition ability of 40 mg/kg·bw dose group, 80 mg/kg·bw dose group and 320 mg/kg·bw dose group was significantly lower than that of control group(P<0.01). The malondialdehyde(MDA) content of 40 mg/kg·bw dose group was significantly higher than that of control group and 80 mg/kg·bw dose group(P<0.01). The serum catalase(CAT) activity of 80 mg/kg·bw dose group was significantly higher than that of 40 mg/kg·bw dose group and 160 mg/kg·bw dose group and 320 mg/kg·bw dose group(P<0.01). According to the results of pathology examination, small intestinal mucosa structure was incomplete, intestinal villus appeared rupture, mucosal epithelium was deciduous. Cardiac muscle fiber was fractured, myocardial cell was intumescent, cardiac muscle cell nucleus was dissolved, and shape of cell nucleus was irregular. Arrangement of liver cells was irregular. Few nucleuses were dissolved. Inflammatory cell infiltration was found at certain region of liver. Few kidney glomeruli were atrophica. The results indicate that the 90 days exposure to nano zinc oxide can influence the antioxidant system of the mice, lead to iron deficiency anemia of mice, cause injury to the small intestine, liver, kidney, heart and other organs.Trial 3 Study on the influence of nano Zinc Oxide on anti-oxidant ability of liver and blood lipid in miceTo detect the effects of nano zinc oxide on blood lipid in mice, mice were continuous infected with different doses of nano zinc oxide through intragastric administration. After 90 d, the blood lipid, liver, anti-oxidation index were measured. The results showed blood glucose of control group, 80 mg/kg·bw dose group was significantly higher than 160 mg/kg·bw dose group(P<0.05), and 40 mg/kg·bw dose group(P<0.01). The blood lipid content of 40 mg/kg·bw dose group, 80 mg/kg·bw dose group was significantly higher than the control group(P<0.05). The blood lipid levels of 160 mg/kg·bw dose group was significantly higher than that of control group(P< 0.01). The serum total cholesterol of 40 mg/kg·bw dose group, 160 mg/kg·bw dose group mice was significantly higher than that of control group(P<0.05). The serum low density lipoprotein content of 40 mg/kg·bw dose group was significantly higher than control group, 80 mg/kg·bw dose group(P<0.05). Serum high density lipoprotein content had no significant differences between groups. 80 mg/kg bw, dose group, 160 mg/kg·bw dose group mice liver catalase activity is significantly higher than control group, 40 mg/kg·bw dose group(P<0.05). The rats liver catalase activity of 80 mg/kg·bw dose group was significantly higher than 40 mg/kg·bw, dose group(P<0.01). The liver Cu-ZnSOD activity of 40 mg/kg·bw dose group, 80 mg/kg·bw dose group mice was significantly higher than control group(P<0.05). The hydroxyl free radical inhibiting ability of 160 mg/kg·bw dose group was significantly lower than the control group, 40 mg/kg·bw dose group and 80 mg/kg·bw dose group(P<0.05). With the increase of infected dose, the MDA content increased, but the content is not significant difference between groups. With the increase of infected dose, mice hepatic glutathione peroxidase activity increased, the activity differences between groups was not significant. There was no liver significant difference of H2O2 content, total SOD activity between groups. Results indicate that 90 d exposure of nano zinc oxide can affect the mice liver antioxidant system, cause lipid metabolism disorder and hyperlipidemia.