Noninvasive in vivo electron paramagnetic resonance study to estimate pulmonary reducing ability in mice exposed to NiO or C60 nanoparticles.

PURPOSE: To develop new methods that can estimate the influences of manufactured nanomaterials on biological systems, the in vivo pulmonary reducing ability of mice that had received inhalation exposures to NiO or C60 nanoparticles was investigated using a 700 MHz electron paramagnetic resonance (EPR) spectrometer.

MATERIALS AND

METHODS

NiO or C60 suspensions were atomized and mice in exposure chambers inhaled the resulting aerosol particles for 3 hours. The exposure conditions, number-based geometric average diameters, and the average number concentration were precisely controlled at almost the same levels for both NiO and C60 nanoparticles. Two days or 2 weeks after exposure, an EPR study was conducted noninvasively. Temporal changes in EPR signal intensity at the target area (ie, lung field) were obtained by the region-selected intensity determination (RSID) method.

RESULTS

NiO nanoparticles significantly suppressed pulmonary reducing ability 2 days and 2 weeks after exposure, but C60 nanoparticles had no such effect.

CONCLUSION

This is the first in vivo estimation of the reducing ability in experimental animals exposed to manufactured nanoparticles.