Yong Soon Kima, Jin Sik Kima, Hyun Sun Choa, Dae Sik Rhaa, Jae Min Kima, Jung Duck Parkb, Byung Sun Choib, Ruth Limb, Hee Kyung Changc, Yong Hyun Chungd, Il Hoon Kwone, Jayoung Jeongf, Beom Seok Hanf and Il Je Yua,g
aKorea Environment & Merchandise Testing Institute, Incheon, Korea
bCollege of Medicine, Chung-Ang University, Seoul, Korea
cDeparment of Pathology, Kosin University, Busan, Korea
dOccupational Safety and Health Research Institute, Korea Occupational Safety Health Agency, Daejeon, Korea
eNational Institute of Scientific Investigation, Seoul, Korea
gKorea Environment and Merchandise Testing Institute, 7-44 Songdo-dong, Yeonsu-gu, Incheon, 406-130, South Korea
*Address correspondence to Il Je Yu
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.