Title page for ETD etd-09182008-063320

Type of Document Master's Thesis
Author Hart, Laura J.
URN etd-09182008-063320
Title 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)
Degree Master of Science
Department Veterinary Medical Sciences
Advisory Committee
Advisor Name Title
Holladay, Steven D. Committee Chair
Nagarkatti, Mitzi Committee Member
Smith, Bonnie J. Committee Member
Smith, Stephen A. Committee Member
  • flow cytometry
  • histology
  • immunosuppression
  • fish hematopoietic organs
  • macrophage
Date of Defense 1996-07-15
Availability restricted
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 hematopoietic organs.

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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