Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA075

Poster Communications

Time-dependent acute lung and spermatic toxicity of exposure to C60 fullerene in mice

F. G. Pinheiro2,1, M. D. Moreira-Gomes2,1, M. N. Machado1, T. S. Almeida1, P. A. Barboza1, L. F. Oliveira3, F. S. Cavalcante4, J. H. Leal-Cardoso2, W. A. Zin1

1. Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil. 2. Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Ceará, Brazil. 3. University Center La Salle, Porto Alegre, Rio Grande do Sul, Brazil. 4. State University of Ceará, Fortaleza, Ceará, Brazil.

C60 fullerene (C60) is released into the atmosphere by anthropogenic and natural sources. Scanty information exists regarding its toxicological effects on respiratory and reproductive systems. We aimed to study the time course of C60-triggered pulmonary and spermatic impairments until 4 days after exposure. The study was approved by our institutional Ethics Committee on the Use of Animals (license: 139/16) and conducted according to ARRIVE guidelines and national legislation. 64 male BALB/c mice randomly composed 8 groups (n=8/group). They were anesthetized (sevoflurane) via a nasal cone, intratracheally instilled with 30 μL of vehicle (1.0% polysorbate 80 in 0.9% NaCl) or 30 μL of C60 (1.0 mg/kg), and studied at 12, 24, 72 and 96 h (F12, F24, F72 and F96 groups and their corresponding controls) after exposure. At each time point, the respective groups underwent sedation (diazepam, 1 mg ip), anaesthesia (pentobarbital sodium, 20 mg/kg ip) and muscle paralysis (pancuronium bromide, 0.1 mg/kg iv). Since no difference was found among the 4 control groups (ANOVA), 2 animals randomly picked from each one composed one single control group (CTRL). Lung mechanics and morphological parameters were determined by a forced oscillation technique and microscopy, respectively. Antioxidant enzymes, oxidative damage and inflammatory cytokines were determined in lung homogenate. Number, motility and vitality of epididymal sperm were determined. Values are means ± S.D., and groups were compared by ANOVA, α = 5%. Morphofunctional and inflammatory data presented peak impairment at 24 h and subsequent decline until 96 h after instillation: tissue damping (CTRL: 2.8±0.5 vs. F24: 4.1±0.4 vs. F96: 2.7±0.4 cmH2O/mL), elastance (CTRL: 21.7±0.8 vs. F24: 30.8±1.1 vs. F96: 23.0±2.7 cmH2O/mL), area of collapsed alveoli (CTRL: 9.0±1.7 vs. F24: 29.8±1.5 vs. F96: 20.7±2.0 % of total area), mononuclear cells (CTRL: 5.9±0.6 vs. F24: 9.6±0.8 vs. F96: 6.6±0.3 cells10-3/mm2 of tissue area), TNF-α (CTRL: 130.1±15.2 vs. F24: 549.2±58.0 vs. F96: 223.5±20.2 ng/mL) and IL-6 (CTRL: 58.9±2.1 vs. F24: 117.0±23.6 vs. F96: 91.9±9.7 ng/mL). There was a time-dependent imbalance in catalase activity (CTRL: 5.6±0.4 vs. F96: 8.7±0.7 U/mg protein), superoxide dismutase (CTRL: 15.4±0.6 vs. F96: 10.7±1.1 U/mg protein) and thiol (CTRL: 0.12±0.01 vs. F96: 0.08±0.007 nmol reduced 5,5'dithiobis-(2-nitrobenzoic acid)/mg protein). Sperm count (CTRL: 38.1±11.8 vs. F12: 26.8±3.3 vs. F96: 15.8±2.2 x 105 spermatozoa/mL), motility (CTRL: 58.7±4.9 vs. F96: 37.6±4.4 % of total count) and vitality (live:dead ratio, CTRL: 2.0±0.1 vs. F24: 0.4±0.1 vs. F96: 0.2±0.05) diminished progressively. In conclusion, possibly a single dose of C60 can induce morphofunctional, inflammatory changes (peak at 24 h) and redox imbalance in mice lungs (highest at 96 h) and progressively increase the risk of infertility. Supported by: CNPq, FAPERJ, FUNCAP

Where applicable, experiments conform with Society ethical requirements