Document Type

Thesis

Date of Award

5-2006

School/College

Barbara Jordan-Mickey Leland School of Public Affairs (SOPA)

Degree Name

Doctor of Education

First Advisor

Professor James DuMond

Abstract

Research has shown that microgravity induces oxidative stress. In this study, we examined the testis from 6-8 weeks old BALB mice exposed to the ground hind-limb unloading model for 7 days. This model has been shown to simulate a microgravity environment. Total RNA was isolated from the testes of both treatment and control groups and Quantitative Real-Time PCR was performed to analyze the expression of genes controlling DNA excision repair pathways. Manganese superoxide dismutase (MnSOD) gene was examined to detect oxidative stress; and the PCNA (Proliferating Cell Nuclear Antigen) gene expression was analyzed to detect repair synthesis as well as cell 1 2 proliferation. Gene expression values were normalized to the house keeping gene Beta Actin. Significant down regulation of the Excision Repair Cross Complementing (ERCCl, ERCC3, ERCC5 and ERCC6) genes were detected. A corresponding decline in the level of PCNA, which indicates a reduction in repair synthesis and cell proliferation, was also detected. Most remarkable was the increased expression of MnSOD (p < 0.005) suggesting that the testes were undergoing increased oxidative stress. These results indicate that exposure to a microgravity environment may adversely affect the testes.

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