Although
organophosphate (OP)-induced
acetylcholinesterase (AChE) inhibition is the critical mechanism causing toxicities that follow exposure, other biochemical events, including oxidative stress, have been reported to contribute to OP toxicity.
Fullerenes are
carbon spheres with
antioxidant activity. Thus, we hypothesized that
fullerenes could counteract the effects of OP compounds and tested this hypothesis using two in vitro test systems, hen brain and human
neuroblastoma SH-SY5Y cells. Cells were incubated with eight different derivatized
fullerene compounds before challenge with
paraoxon (0=control, 5×10(-8), 10(-7), 2×10(-7) or 5×10(-7) M) or diisopropylphosphorofluoridate (
DFP, 0=control, 5×10(-6), 10(-5), 2×10(-5), and 5×10(-5) M) and measurement of AChE activities. Activities of brain and SH-SY5Y AChE with OP compounds alone ranged from 55-83% lower than non-treated controls after
paraoxon and from 60-92% lower than non-treated controls after
DFP. Most incubations containing 1 and 10 μM
fullerene derivatives brought AChE activity closer to untreated controls, with improvements in AChE activity often >20%. Using dissipation of
superoxide anion radicals as an
indicator (
xanthine oxidation as a positive control), all
fullerene derivatives demonstrated significant
antioxidant capability in
neuroblastoma cells at 1 μM concentrations. No
fullerene derivative at 1 μM significantly affected
neuroblastoma cell viability, when determined using either
Alamar Blue dye retention or a luminescent assay for
ATP production. These studies suggest that derivatized
fullerene nanomaterials have potential capability to ameliorate OP-induced AChE inhibition resulting in toxicities.