Title page for ETD etd-09182008-063320
|Type of Document
||Hart, Laura J.
||Subacute immunotoxic effects of the environmental contaminants 7,12-dimethylbenzanthracene (DMBA), hexachlorocyclohexane (lindane), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on spleen and pronephros cellularity and morphology and functional activity of macrophages contained in these hemotopoietic organs in the cichlid fish tilapia (Oreochromis niloticus)
||Master of Science
||Veterinary Medical Sciences
|Holladay, Steven D.
|Smith, Bonnie J.
|Smith, Stephen A.
- flow cytometry
- fish hematopoietic organs
|Date of Defense
Alterations of immune parameters were investigated in fish
exposed to non-overtly toxic levels of three different
environmentally relevant chemicals, 7,12-dimethylbenzanthracene
(DMBA), hexachlorocyclohexane (lindane), and 2,3,7,8-
tetrachlorodibenzo-p -dioxin (TCDD). Each chemical agent was
administered to tilapia in separate experiments by intraperitoneal
injection for five consecutive days. Following the final dose, total
cellularity and histology of the spleen and pronephros were
assessed, as were activity of phagocytic celis contained in these
Using chemical doses which produced no clinical toxicity, tilapia
exposed to each chemical agent displayed a significant reduction in
total cell number of both spleen and pronephros, in most cases in a
dose-related manner. Consistent with this observation, splenic and
pronephric hypocellularity was confirmed upon histological
examination of chemical-treated fish. However, neither superoxide
radical production or phagocytosis of splenic or pronephric
macrophages was inhibited in either DMBA, lindane, or TCDD exposed
fish. Results of this study indicate that depressed total cell number
in fish hematopoietic organs may be a more sensitive indicator of
exposure to these environmental contaminants than is the activity
of macrophages contained within these organs.
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