Type of Document Master's Thesis Author Punareewattana, Korawuth Author's Email Address email@example.com URN etd-110399-160727 Title Immune Function Determination in Mice Dermally Exposed to Permethrin Degree Master of Science Department Veterinary Medical Sciences Advisory Committee
Advisor Name Title Holladay, Steven D. Committee Chair Robertson, John L. Committee Member Smith, Bonnie J. Committee Member Keywords
- Risk assessment
Date of Defense 1999-10-25 Availability unrestricted AbstractInhibited immune responses have been observed following occupational, inadvertent, or therapeutic exposure to chemically diverse xenobiotics. In the present studies, preliminary data were generated showing limited but significant systemic immunotoxicity following low-level topical exposure to the pyrethroid insecticide, permethrin (formerly not considered an immunotoxicant). Permethrin was applied to the shaved dorsal interscapular region of C57Bl/6N mice at doses of 0.5, 1.5, or 5.0 µ l/day. The highest of these doses was approximately equal to 215 µ g/kg/day, which is about seven times the estimated daily human exposure in individuals wearing permethrin treated clothing for insect protection. Mice were thus exposed to permethrin daily for 10 or 30 consecutive days, or every other day for 7 or 14 exposures. Body weight was not affected by the treatment. However thymic weight was decreased and splenic weight increased 2 days after termination of the topical exposure. Histopathology of immune organs showed no significant changes. Splenic macrophages showed significantly depressed chemiluminescent responses up to 10 days following termination of exposure, but macrophage phagocytic activity was not affected. Cell surface markers of thymocytes, splenocytes and bone marrow cells were not affected. Antibody production as shown by plaque forming cell (PFC) assay decreased significantly at 10 days after dosing termination. Taken together, these data indicate that low-level topical permethrin exposure may produce systemic immunotoxicity.
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