Department of Pathophysiology, Defense Health Laboratory Institute, Medical Centre of Hungarian Defense Forces
H-1134, Róbert Károly krt. 44, Budapest, Hungary
Literature data indicate that cytoxicity of carbon nanotubes can be mitigated by peroxidases (Zhao et al. (2011) J Phys Chem 115, 9536-9544; Vlasova et al., (2012) Toxicol Appl Pharmacol, 264,131-142). Our recent studies show that various nanoparticles (single walled carbon nanotube (SWCNT), pegylated-SWCNT, carbon black) induce well detectable peroxidase activity in whole blood. It is obvious to presume that this peroxidase activity can be attributed to the myeloperoxidase released from the azurophil granules if granulocytes were activated. Release of myeloperoxidase from the azurophil granules would be concomitant with the release of beta-glucoronidase and the surface expression of CD63. Formerly, we presented flow cytometric data that PEG-SWCNT strongly induced platelet-granulocyte complex formation in whole blood where the CD63 activation marker detected within the complex could be solely attributed to the platelets and the uncomplexed granulocytes did not express CD 63 on their surface (3rd Virtual Nanotechnology Poster Conference, 2013, (P13-12)). In accordance with our flow cytometric studies no beta-glucuronidase activity could be detected in our systems further supporting that no azurophil granule release takes place in whole blood in the presence of the above nanoparticles. In addition when isolated granulocytes were incubated with the nanoparticles in culture medium no peroxidase activity could be detected. The origin of the peroxidase activity induced by the nanoparticles in the whole blood needs to be further clarified.