title: Exposure to Palladium Nanoparticles Affects Serum Levels of Cytokines in Female Wistar Rats.
abstract: BACKGROUND
  Information currently available on the impact of palladium on the immune system mainly derives from studies assessing the biological effects of palladium salts. However, in the last years, there has been a notable increase in occupational and environmental levels of fine and ultrafine palladium particles released from automobile catalytic converters, which may play a role in palladium sensitization. In this context, the evaluation of the possible effects exerted by palladium nanoparticles (Pd-NPs) on the immune system is essential to comprehensively assess palladium immunotoxic potential.
  
  
  OBJECTIVE
  Therefore, the aim of this study was to investigate the effects of Pd-NPs on the immune system of female Wistar rats exposed to this xenobiotic for 14 days, by assessing possible quantitative changes in a number of cytokines: IL-1α, IL-2, IL-4, IL-6, IL-10, IL-12, GM-CSF, INF-γ and TNF-α.
  
  
  METHODS
  Twenty rats were randomly divided into four exposure groups and one of control. Animals were given a single tail vein injection of vehicle (control group) and different concentrations of Pd-NPs (0.012, 0.12, 1.2 and 12 μg/kg). A multiplex biometric enzyme linked immunosorbent assay was used to evaluate cytokine serum levels.
  
  
  RESULTS
  The mean serum concentrations of all cytokines decreased after the administration of 0.012 μg/kg of Pd-NPs, whereas exceeded the control levels at higher exposure doses. The highest concentration of Pd-NPs (12 μg/kg) induced a significant increase of IL-1α, IL-4, IL-6, IL-10, IL-12, GM-CSF and INF-γ compared to controls.
  
  
  CONCLUSIONS
  These results demonstrated that Pd-NP exposure can affect the immune response of rats inducing a stimulatory action that becomes significant at the highest administered dose. Our findings did not show an imbalance between cytokines produced by CD4+ T helper (Th) cells 1 and 2, thus suggesting a generalized stimulation of the immune system with a simultaneous activation and polarization of the naïve T cells towards Th1 and Th2 phenotype.
authors.affiliation: Institute of Public Health, Section of Occupational Medicine, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168, Rome, Italy.
authors.forename: Ivo
authors.initials: I
authors.lastname: Iavicoli
authors.affiliation: Institute of Public Health, Section of Occupational Medicine, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168, Rome, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Fontana
authors.affiliation: Institute of General Pathology, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168, Rome, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Corbi
authors.affiliation: Institute of Public Health, Section of Occupational Medicine, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168, Rome, Italy.
authors.forename: Veruscka
authors.initials: V
authors.lastname: Leso
authors.affiliation: Epidemiology Unit, Occupational Medicine Department, Research Division, Italian Workers' Compensation Authority (INAIL), Via Alessandria, 220/E, 00198, Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Marinaccio
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Albert Einstein-Str. 11, 89081, Ulm, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Leopold
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Albert Einstein-Str. 11, 89081, Ulm, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Schindl
authors.affiliation: Institute of General Pathology, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168, Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sgambato
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000008:administration & dosage* / Q000633:toxicity; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000276:immunology; D015262:Xenobiotics / Q000008:administration & dosage* / Q000633:toxicity
chemical_list: D016207:Cytokines; D015262:Xenobiotics; D010165:Palladium