Sensitizing Potential of Chromated Copper Arsenate in Local Lymph Node Assays Differs with the Solvent Used

Evaluation of the skin sensitization potential of metal oxide nanoparticles using the ARE-Nrf2 Luciferase KeratinoSensTM assay

Numerous studies have reported the potential of chemicals for inducing skin sensitization; however, few studies have examined skin sensitization induced by nanomaterials. This study aimed to evaluate skin sensitization induced by metal oxide nanoparticles (NPs) using the ARE-Nrf2 Luciferase KeratinoSens™ assay. Seven different metal oxide NPs, including copper oxide, cobalt oxide, nickel oxide, titanium oxide, cerium oxide, iron oxide, and zinc oxide, were assessed on KeratinoSens™ cells. We selected an appropriate vehicle among three vehicles (DMSO, DW, and culture medium) by assessing the hydrodynamic size at vehicle selection process. Seven metal oxide NPs were analyzed, and their physicochemical properties, including hydrodynamic size, polydispersity, and zeta potential, were determined in the selected vehicle. Thereafter, we assessed the sensitization potential of the NPs using the ARE-Nrf2 Luciferase KeratinoSens™ assay. Copper oxide NPs induced a positive response, whereas cobalt oxide, nickel oxide, titanium oxide, cerium oxide, iron oxide, and zinc oxide NPs induced no response. These results suggest that the ARE-Nrf2 Luciferase KeratinoSens™ assay may be useful for evaluating the potential for skin sensitization induced by metal oxide NPs.

Pathological and Clinical Pathological Changes Induced by Four-week, Repeated-dose, Oral Administration of the Wood Preservative Chromated Copper Arsenate in Wistar Rats

Chromated copper arsenate (CCA) is used as a wood preservative worldwide. Exposure to it may adversely affect human health. Some events have increased human exposure to CCA, including the Great East Japan Earthquake, which generated a large amount of lumber debris from CCA-treated woods. We elucidated the toxicity due to daily exposure to CCA over a 4-week period at doses of 0, 8, 40, and 80 mg/kg/day in Wistar Hannover rats. Chromium (Cr) and arsenic (As), but not copper, were detected in the plasma samples of rats treated with various doses of CCA. Males and females showed sedation, and males had poor body weight gain. The clinical pathologies observed in both sexes included hypochromic and microcytic anemia, hepatic and renal dysfunction, and changes in lipid and glucose levels. Histopathologically, males and females showed forestomach hyperkeratosis, mucosal epithelial hyperplasia in the small intestine, rectal goblet cell hypertrophy, and lipofuscin deposition in the proximal renal tubule. Females showed diffuse hepatocellular hypertrophy with increased 8-hydroxydeoxyguanosine levels. These results indicated that oral administration of CCA mainly affected hematopoietic, gastrointestinal, hepatic, and renal systems owing to the toxic effects of As and/or Cr. Major toxic effects were observed in both sexes receiving 40 and 80 mg/kg/day.