title: Twenty-eight-day repeated inhalation toxicity study of nano-sized lanthanum oxide in male sprague-dawley rats.
abstract: Although the use of lanthanum has increased in field of high-tech industry worldwide, potential adverse effects to human health and to the environment are largely unknown. The present study aimed to investigate the potential toxicity of nano-sized lanthanum oxide (La2O3) following repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed nose-only to nano-sized La2O3for 28 days (5 days/week) at doses of 0, 0.5, 2.5, and 10 mg/m3. In the experimental period, we evaluated treatment-related changes including clinical signs, body weight, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology findings. We also analyzed lanthanum distribution in the major organs and in the blood, bronchoalveolar lavage fluids (BALF), and oxidative stress in lung tissues. Lanthanum level was highest in lung tissues and showed a dose-dependent relation. Alveolar proteinosis was observed in all treatment groups and was accompanied by an increase in lung weight; moreover, lung inflammation was observed in the 2.5 mg/m3and higher dose groups and was accompanied by an increase in white blood cells. In the BALF, total cell counts including macrophages and neutrophils, lactate dehydrogenase, albumin, nitric oxide, and tumor necrosis factor-alpha increased significantly in all treatment groups. Furthermore, these changes tended to deteriorate in the 10 mg/m3group at the end of the recovery period. In the present experimental conditions, we found that the lowest-observed-adverse-effect level of nano-sized La2O3was 0.5 mg/m3in male rats, and the target organ was the lung. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1226-1240, 2017.
authors.affiliation: Center for Chemicals Safety and Health, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122, Republic of Korea.|College of Veterinary Medicine BK21 Plus Project Team, Chonnam National University, Gwangju, 61186, Republic of Korea.
authors.forename: Seo-Ho
authors.initials: SH
authors.lastname: Shin
authors.affiliation: Center for Chemicals Safety and Health, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122, Republic of Korea.
authors.forename: Cheol-Hong
authors.initials: CH
authors.lastname: Lim
authors.affiliation: Center for Chemicals Safety and Health, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122, Republic of Korea.
authors.forename: Yong-Soon
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Center for Chemicals Safety and Health, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122, Republic of Korea.
authors.forename: Yong-Hoon
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, Jeongeup, Jeonbuk, 53212, Republic of Korea.
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Kim
authors.affiliation: College of Veterinary Medicine BK21 Plus Project Team, Chonnam National University, Gwangju, 61186, Republic of Korea.
authors.forename: Jong-Choon
authors.initials: JC
authors.lastname: Kim
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D007770:L-Lactate Dehydrogenase / Q000097:blood; D007811:Lanthanum / Q000737:chemistry*; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000166:cytology; D008297:Male; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D009504:Neutrophils / Q000166:cytology; D009569:Nitric Oxide / Q000032:analysis; D018384:Oxidative Stress / Q000187:drug effects*; D010087:Oxides / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D010087:Oxides; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; C103829:lanthanum oxide; D007811:Lanthanum; D007770:L-Lactate Dehydrogenase
keywords: inhalation toxicity; lowest-observed-adverse-effect level; nano-sized lanthanum oxide; target organ