| Popis: |
Bozena Novotna,1 Vit Herynek,2 Pavel Rossner Jr,1 Karolina Turnovcova,3 Pavla Jendelova3 1Department of Genetic Toxicology and Nanotoxicology, Institute of Experimental Medicine AS CR, v.v.i., 2Magnetic Resonance Unit, Radiodiagnostic and Interventional Radiology Department, Institute for Clinical and Experimental Medicine, 3Department of Tissue Culture and Stem Cells, Institute of Experimental Medicine AS CR, v.v.i., Prague, Czech Republic Introduction: Rat mesenchymal stem cells (rMSCs) labeled with 1) poly-l-lysine-coated superparamagnetic iron oxide nanoparticles or 2) silica-coated cobalt-zinc-iron nanoparticles were implanted into the left brain hemisphere of rats, to assess their effects on the levels of oxidative damage to biological macromolecules in brain tissue.Methods: Controls were implanted with unlabeled rMSCs. Animals were sacrificed 24 hours or 4 weeks after the treatment, and the implantation site along with the surrounding tissue was isolated from the brain. At the same intervals, parallel groups of animals were scanned in vivo by magnetic resonance imaging (MRI). The comet assay with enzymes of excision DNA repair (endonuclease III and formamidopyrimidine-DNA glycosylase) was used to analyze breaks and oxidative damage to DNA in the brain tissue. Oxidative damage to proteins and lipids was determined by measuring the levels of carbonyl groups and 15-F2t-isoprostane (enzyme-linked immunosorbent assay). MRI displayed implants of labeled cells as extensive hypointense areas in the brain tissue. In histological sections, the expression of glial fibrillary acidic protein and CD68 was analyzed to detect astrogliosis and inflammatory response.Results: Both contrast labels caused a similar response in the T2-weighted magnetic resonance (MR) image and the signal was clearly visible within 4 weeks after implantation of rMSCs. No increase of oxidative damage to DNA, lipids, or proteins over the control values was detected in any sample of brain tissue from the treated animals. Also, immunohistochemistry did not indicate any serious tissue impairment around the graft.Conclusion: Both tested types of nanoparticles appear to be prospective and safe labels for tracking the transplanted cells by MR. Keywords: MRI, comet assay, genotoxicity, lipid peroxidation, protein oxidative damage, cell transplantation |
