TY - JOUR
T1 - Phototoxicity and cytotoxicity of fullerol in human lens epithelial cells
AU - Roberts, Joan E.
AU - Wielgus, Albert R.
AU - Boyes, William K.
AU - Andley, Usha
AU - Chignell, Colin F.
N1 - Funding Information:
This research was supported by the Intramural Research Program of the National Institutes of Health, National Institute of Environmental Health Sciences. We wish to thank Dr. Ann Motten of the National Institute of Environmental Health Sciences (NIEHS) for the help in preparation of this manuscript and Dr. Carl Bortner and Maria Sifre for their assistance with flow cytometry measurements. Images of the cells were taken by C. Jeff Tucker at the NIEHS Fluorescence Microscopy and Imaging Center. The images of the whole lenses were taken by Steve McCaw and the figure of fullerol was designed by David Green both of NIEHS Arts and Photograph Center. We also wish to thank Dr. Nigel Walker of National Toxicology Program, NIEHS for supplying the fullerol used in these experiments and Dr. Laura Degn of the US Environmental Protection Agency (USEPA) for the assistance with dynamic light scattering measurements. This manuscript has been reviewed by the National Health and Environmental Effects Research Laboratory, USEPA and NIEHS and approved for publication. Mention of trade names and commercial products does not constitute endorsement or recommendation for use.
PY - 2008/4/1
Y1 - 2008/4/1
N2 - The water-soluble, hydroxylated fullerene [fullerol, nano-C60(OH)22-26] has several clinical applications including use as a drug carrier to bypass the blood ocular barriers. We have assessed fullerol's potential ocular toxicity by measuring its cytotoxicity and phototoxicity induced by UVA and visible light in vitro with human lens epithelial cells (HLE B-3). Accumulation of nano-C60(OH)22-26 in the cells was confirmed spectrophotometrically at 405 nm and cell viability estimated using MTS and LDH assays. Fullerol was cytotoxic to HLE B-3 cells maintained in the dark at concentrations higher than 20 μM. Exposure to either UVA or visible light in the presence of > 5 μM fullerol-induced phototoxic damage. When cells were pretreated with non-toxic antioxidants: 20 μM lutein, 1 mM N-acetyl cysteine, or 1 mM l-ascorbic acid prior to irradiation, only the singlet oxygen quencher-lutein significantly protected against fullerol photodamage. Apoptosis was observed in lens cells treated with fullerol whether or not the cells were irradiated, in the order UVA > visible light > dark. Dynamic light scattering (DLS) showed that in the presence of the endogenous lens protein α-crystallin, large aggregates of fullerol were reduced. In conclusion, fullerol is both cytotoxic and phototoxic to human lens epithelial cells. Although the acute toxicity of water-soluble nano-C60(OH)22-26 is low, these compounds are retained in the body for long periods, raising concern for their chronic toxic effect. Before fullerols are used to deliver drugs to the eye, they should be tested for photo- and cytotoxicity in vivo.
AB - The water-soluble, hydroxylated fullerene [fullerol, nano-C60(OH)22-26] has several clinical applications including use as a drug carrier to bypass the blood ocular barriers. We have assessed fullerol's potential ocular toxicity by measuring its cytotoxicity and phototoxicity induced by UVA and visible light in vitro with human lens epithelial cells (HLE B-3). Accumulation of nano-C60(OH)22-26 in the cells was confirmed spectrophotometrically at 405 nm and cell viability estimated using MTS and LDH assays. Fullerol was cytotoxic to HLE B-3 cells maintained in the dark at concentrations higher than 20 μM. Exposure to either UVA or visible light in the presence of > 5 μM fullerol-induced phototoxic damage. When cells were pretreated with non-toxic antioxidants: 20 μM lutein, 1 mM N-acetyl cysteine, or 1 mM l-ascorbic acid prior to irradiation, only the singlet oxygen quencher-lutein significantly protected against fullerol photodamage. Apoptosis was observed in lens cells treated with fullerol whether or not the cells were irradiated, in the order UVA > visible light > dark. Dynamic light scattering (DLS) showed that in the presence of the endogenous lens protein α-crystallin, large aggregates of fullerol were reduced. In conclusion, fullerol is both cytotoxic and phototoxic to human lens epithelial cells. Although the acute toxicity of water-soluble nano-C60(OH)22-26 is low, these compounds are retained in the body for long periods, raising concern for their chronic toxic effect. Before fullerols are used to deliver drugs to the eye, they should be tested for photo- and cytotoxicity in vivo.
KW - Dynamic light scattering
KW - Fullerenes
KW - Fullerol
KW - Human lens epithelial cells
KW - Ocular toxicology
KW - Phototoxicity
UR - http://www.scopus.com/inward/record.url?scp=40849085094&partnerID=8YFLogxK
U2 - 10.1016/j.taap.2007.12.010
DO - 10.1016/j.taap.2007.12.010
M3 - Article
C2 - 18234258
AN - SCOPUS:40849085094
SN - 0041-008X
VL - 228
SP - 49
EP - 58
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
IS - 1
ER -