Vipula Petluru

Publication Date

5-2007

Advisor(s) - Committee Chair

Cheryl Davis, Kenneth Crawford, Claire Rinehart

Comments

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Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

Previous studies in our laboratory have shown that dietary supplementation with vitamin E and selenium during murine infection with Toxoplasma gondii results in increased tissue cyst number, tissue pathology, and weight loss in both resistant and susceptible mouse strains. Real-time reverse transcriptase PCR (Real-time RT-PCR) and microarray analysis of gene expression has also revealed an intense inflammatory response in the brains of infected mice supplemented with antioxidants. The purpose of the present study was to investigate the impact of antioxidant supplementation on the production of nitric oxide and inducible nitric oxide synthases (NOS2) in this murine model of T. gondii infection. Production of nitric oxide during acute infection with T. gondii has been shown to have a potent microbicidal effect on intracellular stages of the parasite. It also has been shown to induce apoptosis in a number of cell types, including macrophages. Total nitric oxide present in mouse sera was quantified using a colorimetric assay based upon the Griess reaction. Levels of NOS2 gene expression in mouse brains and spleens were quantified by Real-time RT-PCR. Serum nitrate levels were significantly higher in both groups of T. gondii infected mice as compared to non-infected control mice. In addition, serum nitrate levels were significantly higher in mice maintained on a diet deficient in antioxidants as compared to mice maintained on an antioxidant supplemented diet (p=0.01). Gene expression analysis showed that NOS2 mRNA levels were also significantly elevated in the brains and spleens of mice infected with T. gondii as compared to non-infected control mice. Whereas the mean NOS2 levels in the brains and spleens of infected mice maintained on the antioxidant deficient diet were higher than levels observed in infected mice maintained on an antioxidant supplemented diet, these differences were statistically significant. The results of this study demonstrate that diet can impact levels of NO sysnthesis in this experimental model of toxoplasmosis. Additional experiments will be required to fully investigate the impact of antioxidant supplementation and antioxidant deficiency on NOS2 gene expression.

Disciplines

Biology | Life Sciences

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