Date of Award

Winter 2003

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Program/Concentration

Biomedical Sciences

Committee Director

R. James Swanson

Committee Member

Sergio Oehninger

Committee Member

Mahmood S. Morshedi

Abstract

Production of functional gametes and healthy embryos is essential for proliferation of all vertebrates, especially humans. Many compounds have toxic effects on developing gametes and embryos among which are chromium trioxide (CrO3), cupric oxide (CuO) and arsenic pentaoxide (As2O5) as a mixture (CCA) or individually. Controversy surrounding the safety of CCA-treated wood centers primarily on the toxicity of its components and the potential for these metals to be released from the wood.

The aim of this research is to test the hypothesis that CCA components have deleterious effects on embryo development, oocyte maturation and integrity and sperm function.

A two-cell embryo assay was proposed to detect embryotoxicity of the CCA components and their mixtures. Total blastocyst cell numbers, analyzed by fluorescent DNA-binding, were the indicator of embryotoxicity on the subcellular level. Oocytes, in vitro-matured in the presence of CCA components, were analyzed for cell cycle progression. Spindle formation and chromosomal patterns in MI and MII oocytes were analyzed by immunofluorescent staining. A sperm motility index was used to evaluate sperm function in the presence of CCA components. Sperm viability was analyzed using fluorescent staining.

Summarizing our results, embryonic exposure to arsenic, chromium and copper concentrations of as little as 0.5 mg/L have a toxic effect on embryo quality represented by significant reduction in total cell numbers without reduction in the embryonic developmental stages. Increasing the concentration above 0.5 mg/L was accompanied by a dose-dependent decrease in embryonic development in the form of a drop in the number of morula/blastula stage embryos and elevation in fragmented/degenerated embryos. A trace amount of arsenic, chromium or copper inhibits oocyte maturation. The metal compounds delay cell-cycle progression and arrest oocytes in meiosis. Aberrant spindle and chromosome misalignments were a common feature in most MI and MII treated oocytes. The sperm motility index and viability showed a reduction in the presence of trace amount of CCA components.

In conclusion, acute-chronic exposure to arsenic, chromium or copper compounds may affect embryo and gamete development and quality on the cellular-subcellular levels.

Comments

Dissertation submitted to the Faculty of Eastern Virginia Medical School and Old Dominion University in Partial Fulfillment of the Requirement for the Degree of Doctor of Philosophy in Biomedical Sciences.

DOI

10.25777/gg3a-sy32

ISBN

9780496605460

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