Research Accomplishment Reports 2009

Antioxidant Nutrients, Reactive Oxygen Species and Oxidative Stress

C.K. Chow
Department of Human Environmental Sciences

 

Non-Technical Summary

Antioxidant inadequacy and environmental agents cause oxidative stress, which contribute to the pathogenesis of many degenerative diseases. This project examines if antioxidant nutrients, individually or in combination, protect against oxidative damage resulting from environmental stress.

2009 Project Description

Manganese superoxide dismutase (Mn-SOD), which catalyzes the dismutation of superoxide to hydrogen peroxide, is an important antioxidant enzyme in aerobic organisms. Labile iron or free iron associated with low molecule mass has the potential to participate in redox cycling and catalyze the formation of hydroxyl radical from superoxide/hydrogen peroxide. The state and levels of labile iron or available form of iron can be modified by oxidants or reductants acting on cell iron sources. Information obtained from in vitro and cell culture studies suggests that several compounds, including superoxide and hydrogen peroxide, may release iron from such protein complexes as mitochondrial iron-sulfur clusters, transferrin and ferritin. Previous studies have shown that increased expression of Mn-SOD did not alter the status of other antioxidant systems, but it attenuates oxidative damage to membrane lipids. To further determine the role of Mn-SOD gene in cellular antioxidant defense, liver and skeletal muscle of 16 week old male transgenic Mn-SOD mice and their non-transgenic litter mates were analyzed for the rates of mitochondrial hydrogen peroxide generation and the levels of labile iron.

2009 Impact

The results showed that the liver and skeletal muscle of transgenic Mn-SOD mice had significantly lower rates of both mitochondrial hydrogen peroxide generation and the levels of labile iron than and their non-transgenic litter mates. The findings suggest that reduced rate of mitochondrial hydrogen peroxide generation may attenuate iron release from its protein complex, and support the view that the conditions that favor superoxide/hydrogen peroxide generation may also lead to an increased iron release, and initiation of oxidative damage.

2009 Publications

Chow, C.K. (2009)Role of vitamin E in cellular antioxidant defense. Current Chemical Biology 3: 197-202.

Chow, C.K. (2009)Fatty acid composition of plasma phospholipids and risk of prostate cancer. Am. J. Clin. Nutr. 89: 1946-1946.

Chow, C.K. (2009) Dietary β-tocopherol and serum levels of sex hormone-binding globulin. J. Nutr. 139: 2007-2007.