RESUMO
This study was performed to evaluate the toxicity of cadmium selenide for a period of 28 days in Sprague-Dawley rats. Each of 10 healthy male and females rats per group received daily oral administration for 28-day period at dosage levels 30, 300 and 1,000 mg/kg of body weight. Mortality and clinical signs were checked, and body weight, water intake and food consumption were also recorded weekly. There were no dose-related changes in food consumption or urine volume. All animals survived to the end of study with no clinical signs or differences in body weight gain observed when compared with the control group. At the end of study, all animals including control group, were subjected to necropsy. Blood samples were collected for hematology tests including coagulation time and biochemistry analysis. Blood coagulation time and relative organ weight were unaffected by all received doses. White Blood Cell (WBC) counts significantly increased in the 300 mg/ kg administered male animal group when compared to the control. Monocyte (MO) value were also increased significantly in both 300 and 1,000 mg/kg male animal group. However, Mean Corpuscular Volume (MCV) were significantly decreased compared with the control in the 1,000 mg/kg dose groups for male and female animals. Mean Corpuscular Hemoglobin (MCH) decreased significantly for female in the 300 and 1,000 mg/kg group compared to the control. Blood biochemical values of Inorganic phosphorus (IP) were significantly increased in both the 300 and 1,000 mg/kg dose groups in male animals when compared to the control. Creatinine (CRE) levels indicated significant increase in kidney function for the female, 30 mg/kg dose group when compared with control. There was a significant decrease in thymus absolute organ weight in the female, 1,000 mg/kg dose group when compared with control. Histopathological findings revealed no evidence of injury related to cadmium selenide except for one case of focal hepatic inflammation in the high dose (1,000 mg/kg) group. One case of lung inflammation was also seen in the control group. Basis on these result, the No Observable Adverse Effect Level (NOAEL) of cadmium selenide was determined to be more than 1,000 mg/kg/day for male and female rats under conditions in this study.
RESUMO
The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, and home products. However, while the population exposed to silver nanoparticles continues to increase with ever new applications, silver nanoparticles remain a controversial research area as regards their toxicity to biological systems. In particular, the oral toxicity of silver nanoparticles is of particular concern to ensure public and consumer health. Accordingly, this study tested the oral toxicity of silver nanoparticles (60 nm) over a period of 28 days in Sprague-Dawley rats following Organization for Economic Cooperation and Development (OECD) test guideline 407 with Good Laboratory Practice (GLP) application. Eight-week-old rats, weighing about 283 g for the males and 192 g for the females, were divided into four 4 groups (10 rats in each group): vehicle control, low-dose group (30 mg/kg), middle-dose group (300 mg/kg), and high-dose group (1000 mg/kg). After 28 days of exposure, the blood biochemistry and hematology were investigated, along with a histopathological examination and silver distribution study. The male and female rats did not show any significant changes in body weight relative to the doses of silver nanoparticles during the 28-day experiment. However, some significant dose-dependent changes were found in the alkaline phsophatase and cholesterol values in either the male or female rats, seeming to indicate that exposure to over more than 300 mg of silver nanoparticles may result in slight liver damage. There were no statistically significant differences in the micronucleated polychromatic erythrocytes (MN PCEs) or ratio of polychromatic erythrocytes among the total erythrocytes after silver nanoparticle exposure when compared with the control. Therefore, the present results suggest that silver nanoparticles do not induce genetic toxicity in male and female rat bone marrow in vivo. Nonetheless, the tissue distribution of silver nanopaticles did show a dose-dependent accumulation of silver content in all the tissues examined. In particular, a gender-related difference in the accumulation of silver was noted in the kidneys, with a twofold increase in the female kidneys when compared with the male kidneys.
