Single-Dose Topical Exposure To The Pyrethroid Insecticide, Permethrin In C57BL/6N Mice
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Single-Dose Topical Exposure To The Pyrethroid Insecticide, Permethrin In
C57BL/6N Mice
Date:
Sat, 4 Jan 2003 10:54:24 -0500
From:
Stephen Tvedten <steve@getipm.com>
Organization: Get Set Inc. (www.getipm.com)
To: Paul Helliker <phelliker@cdpr.ca.gov>
Director, State of California, Department of Pesticide
Regulation
cc: Christine Whitman whitman.christine@epa.gov
Pyrethroid are persistent pesticides commonly used in the U.S. for pest control. One of its most interesting characteristics is its ability to bind to cloth and to remain there even after thirty washings (the military funded the research that proved this persistence). Because of its ability to remain in fabric-the military directed that it be sprayed on Gulf War veteran's uniforms for insect control.
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Authors: Prater, MR; Gogal, RM; Blaylock, BL; Longstreth, J;
Holladay, SD
Title: Single-dose topical exposure to the pyrethroid insecticide,
permethrin in C57BL/6N mice: effects on thymus and spleen
Source: FOOD AND CHEMICAL TOXICOLOGY, 40 (12): 1863-1873 DEC 2002
Keywords: permethrin; C57BL/6N mouse; pesticide; thymocyte; splenocyte;
chemiluminescence; apoptosis; proliferation; plaque forming cell assay;
lymphocyte phenotypes; immunomodulation
KeyWords Plus: GULF-WAR VETERANS;NONRADIOACTIVE ASSAY; DERMAL
PENETRATION; IMMUNE PARAMETERS; BALB/C MICE; LYMPHOCYTES; TOXICITY;
PROLIFERATION; CYPERMETHRIN; ELIMINATION
Abstract: Immunomodulatory effects of single topical exposure to
permethrin were evaluated in 5-week-old female C571BL/6N mice. Mice exposed to
5-25 mul permethrin (equivalent to 220-1100 mg/kg body weight) on shaved
interscapular skin were evaluated for altered body weight; splenic and thymic
organ weight and cellularity; thymocyte cell surface expression, cellular
apoptosis; splenic macrophage phagocytosis and hydrogen peroxide production;
splenic B cell antibody production and T cell cytolytic activity; and
mitogen-induced proliferation of splenocytes and thymocytes after in vivo or
in vitro permethrin exposure. Topical permethrin application (25 mul) caused
32% inhibition of splenic T cell proliferation; in vitro exposure to
permethrin also diminished splenocyte proliferation by 72% at 25 mum and 86%
at 100 mum. permethrin did not appear to affect other leukocyte functional
assays. Dose-related decreases in thymic cellularity of 52 and 80% were seen
in mice exposed to 15 and 25 mul permethrin, respectively. Apoptosis was
significantly increased in CD4(-)8(-) and CD4(-)8(+) thymocytes, and the
CD4(+) CD8(+) thymocyte subpopulation was most severely diminished, suggesting
possible chemical-induced apoptotic mechanism of thymic atrophy. Permethrin
also caused splenic hypocellularity by 31% at 15 mul, and by 50% at 25 mul, an
effect that may relate to inhibited proliferation or reduced seeding from the
hypocellular thymus. (C) 2002 Elsevier Science Ltd. All rights reserved.
Reprints: PRATER MR,VIRGINIA POLYTECH INST & STATE UNIV,VIRGINIA
MARYLAND REG COLL VET MED DEPT BIOMED SCI & PATHOBIOL; BLACKSBURG VA 24061,
USA. mrprater@vt.edu
Research Institutions: Virginia Polytech Inst & State Univ, Virginia
Maryland Reg Coll Vet Med, Dept Biomed Sci & Pathobiol, Blacksburg, VA 24061
USA. Inst Global Risk Res, Bethesda, MD 20817 USA. Univ Louisiana, Coll Pharm
& Hlth Sci, Monroe, LA 71209 USA.
Discipline: FOOD SCIENCE/NUTRITION PHARMACOLOGY & TOXICOLOGY
CC Editions / Collections: Agriculture, Biology & Environmental
Sciences (ABES); Life Sciences (LS) Language: English Document type: Article
IDS No.: 621PT
Publisher: PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE,
KIDLINGTON, OXFORD OX5 1GB, ENGLAND
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