In vitro genotoxicity studies using complex hydrophobic mixtures: efficient delivery of a petroleum sample to cultured C3H/10T1/2 cells via lipid vesicle incorporation
Petroleum fractions are a diverse group of extremely hydrophobic mixtures, some of which display strong carcinogenicity in animal skin painting experiments. Interpretation of in vitro genotoxicity experiments with these samples is complicated by inefficient delivery of these hydrophobic substances inside target cells. The authors therefore developed methods to assess and improve the efficiency of delivering a petroleum sample (Matrix, A.P.I. 81-17) to cultured C3H/10T1/2 cells for genotoxicity studies via lipid vesicle incorporation. Three radiolabeled compounds (/sup 14/C-benzo(a)pyrene, /sup 14/C-decane, and /sup 14/C-naphthalene) of widely differing volatilities, broadly representative of the spectrum of compounds in petroleum samples, were separately added to Matrix. The classical methods for preparing neutral unilamellar liposomes were the most successful for delivering radiolabeled compounds in Matrix to cells. Vesicles optimal for the delivery of tracers in Matrix were prepared with DSPC:cholesterol:lyso-PC (8.8:0.8:0.4, molar ratio) in a Matrix to lipid ratio of 31:69 (w/w). This new method of delivery resulted in proportional, dose-dependent, and reproducible uptake of all tracers. Further, cells treated with this preparation took up 2.5-fold more /sup 14/C-decane, 1.5-fold more /sup 14/C-BaP, and 18-fold more /sup 14/C-naphthalene added to Matrix than did cells treated with Matrix emulsified in tissue culture medium. In contrast, tracers were not taken up in a proportional or reproducible manner when emulsions were used. Two petroleum fractions, C/sub 2/029188 and C/sub 3/029194, were 4- and 6-fold more cytotoxic, respectively, when delivered to C3H/10T1/2 cells by lipid vesicles than emulsions. The carcinogenic petroleum fraction C/sub 5/0292202 induces type II transformed foci in C3H/10T1/2 cells when cells were treated with C/sub 5/0292202 incorporated into lipid vesicles.
- Research Organization:
- Univ. of Southern California, Los Angeles
- OSTI ID:
- 5242979
- Journal Information:
- Environ. Mutagen.; (United States), Vol. 8:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
BENZOPYRENE
UPTAKE
DECANE
FIBROBLASTS
ONCOGENIC TRANSFORMATIONS
NAPHTHALENE
PETROLEUM
TOXICITY
TRITIUM COMPOUNDS
EMBRYONIC CELLS
LIPIDS
ALKANES
ANIMAL CELLS
AROMATICS
CELL TRANSFORMATIONS
CONDENSED AROMATICS
CONNECTIVE TISSUE CELLS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
LABELLED COMPOUNDS
ORGANIC COMPOUNDS
SOMATIC CELLS
560301* - Chemicals Metabolism & Toxicology- Cells- (-1987)
550601 - Medicine- Unsealed Radionuclides in Diagnostics