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The effect of m-xylene on cytotoxicity and cellular antioxidant status in rat dermal equivalents.

Authors
Coleman-CA; Hull-BE; McDougal-JN; Rogers-JV
Source
Toxicol Lett 2003 Apr; 142(1-2):133-142
NIOSHTIC No.
20029158
Abstract
Exposure of the skin to volatile organic chemicals (VOCs) can lead to irritation, inflammation and cytotoxicity. Since VOCs are used in industrial, commercial and military applications, concern is mounting with respect to VOC safe exposure limits. Although traditional toxicological assessment of VOCs has utilized animal models, the use of alternative in vitro models is becoming more widespread. We have previously developed a sealed exposure system that prevents chemical loss through evaporation and enables calculation of target cell chemical dose. The present study utilized this in vitro exposure method to assess m-xylene-induced cytotoxicity and antioxidant status in dermal equivalents (dermal fibroblasts in a collagen matrix). At the end of a 1- or 4-h exposure, cytotoxicity was measured using the MTT assay and the EC50 values determined were 1481 +/- 88 and 930 +/- 33, respectively. Decreases in cellular thiols and catalase activity were observed, which occurred in a time and dose-dependent manner. Treatment of dermal equivalents with the antioxidants N-acetylcysteine (NAC) and catalase provided some protection against m-xylene-induced cytotoxicity. When compared to m-xylene exposures, treatment with either 1.0 or 5.0 mM NAC led to increases in the EC50 values at 1 and 4 h. Increases in these EC50 values ranged from 1.22- to 1.32-fold at 1 h and 1.27- to 1.54-fold at 4 h. Although treatment with catalase (1000 U/ml) led to a 1.35-fold increase in cell viability at 1 h, no significant differences were observed at either 1 or 4 h when compared to dermal equivalents exposed to m-xylene alone. These results suggest that exposure to m-xylene leads to a time- and dose-dependent decrease in cellular antioxidants and that cellular thiols may provide protection against the cytotoxic properties of m-xylene.
Keywords
Xylenes; Cytotoxicity; Cytotoxins; Cytotoxic-effects; Antioxidants; Antioxidation; Organic-chemicals; Skin-exposure; Skin-irritants; Exposure-limits; In-vitro-studies; In-vitro-study; Exposure-levels; Exposure-assessment
Contact
ManTech, 2856 G Street, Building 79, Wright-Patterson AFB, OH 45433, USA
CODEN
TOLED5
Publication Date
20030430
Document Type
Journal Article
Email Address
james.rogers@wpafb.af.mil
Funding Type
Grant
Fiscal Year
2003
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-000354
Issue of Publication
1-2
ISSN
0378-4274
Source Name
Toxicology Letters
State
OH
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