Western Kentucky University

Impact of Pro-oxidant Diet on Cytokine Production in Mice Infected with Toxoplasma gondii

Institution

Western Kentucky University

Abstract

Toxoplasmosis, particularly toxoplasmic encephalitis has emerged as a major cause of morbidity and mortality in patients with AIDS. Patients infected with HIV typically experience chronic oxidative stress, and concurrent infection with the intracellular parasite, Toxoplasma gondii, would be expected to further exacerbate this condition. However, previous studies in the laboratory have provided evidence that dietary supplementation with antioxidants is actually harmful during experimental Toxoplasmosis in mice, whereas a pro-oxidant diet (deficient in vitamin E and selenium) results in decreased numbers of tissue cysts and dramatically reduced pathology. The present study was designed to measure the levels of various Th1 and Th2 regulatory cytokines in serum samples and in spleen cell culture supernatants in this experimental model. Two groups of 5 Swiss mice received anti-oxidant supplementation, and 2 groups of 5 mice received a diet deficient in vitamin E and selenium. Two additional groups were maintained on a normal diet of Purina Rodent Chow containing the recommended daily allowances of both vitamin E and selenium. After 4 weeks, 1 group of mice from each dietary treatment received an intraperitoneal injection of 1000 tachyzoite stages of Toxoplasma gondii (ME49 strain). At 2 weeks post-infection sera and spleen cell culture supernatants were obtained from all mice (T. gondii infected and non-infected) and cytokine levels were quantified by an antigen capture enzyme linked immunosorbent assay. Preliminary results suggest that protective Th1 cytokine expression is enhanced in the acute phase of infection in mice maintained on a pro-oxidant diet.

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Impact of Pro-oxidant Diet on Cytokine Production in Mice Infected with Toxoplasma gondii

Toxoplasmosis, particularly toxoplasmic encephalitis has emerged as a major cause of morbidity and mortality in patients with AIDS. Patients infected with HIV typically experience chronic oxidative stress, and concurrent infection with the intracellular parasite, Toxoplasma gondii, would be expected to further exacerbate this condition. However, previous studies in the laboratory have provided evidence that dietary supplementation with antioxidants is actually harmful during experimental Toxoplasmosis in mice, whereas a pro-oxidant diet (deficient in vitamin E and selenium) results in decreased numbers of tissue cysts and dramatically reduced pathology. The present study was designed to measure the levels of various Th1 and Th2 regulatory cytokines in serum samples and in spleen cell culture supernatants in this experimental model. Two groups of 5 Swiss mice received anti-oxidant supplementation, and 2 groups of 5 mice received a diet deficient in vitamin E and selenium. Two additional groups were maintained on a normal diet of Purina Rodent Chow containing the recommended daily allowances of both vitamin E and selenium. After 4 weeks, 1 group of mice from each dietary treatment received an intraperitoneal injection of 1000 tachyzoite stages of Toxoplasma gondii (ME49 strain). At 2 weeks post-infection sera and spleen cell culture supernatants were obtained from all mice (T. gondii infected and non-infected) and cytokine levels were quantified by an antigen capture enzyme linked immunosorbent assay. Preliminary results suggest that protective Th1 cytokine expression is enhanced in the acute phase of infection in mice maintained on a pro-oxidant diet.