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Inhibition of nitric oxide production exacerbates chronic ocular toxoplasmosis
Author(s) -
Roberts Fiona,
Roberts Craig W.,
Ferguson David J.P.,
McLeod Rima
Publication year - 2000
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1046/j.1365-3024.2000.00259.x
Subject(s) - toxoplasmosis , nitric oxide , toxoplasma gondii , inflammation , pathogenesis , immunology , retina , nitric oxide synthase , biology , choroid , pathology , medicine , endocrinology , antibody , neuroscience
There is considerable controversy as to the roles of parasite proliferation and the inflammatory response in destruction of the retina during Toxoplasma gondii infection. A murine model was used to investigate the role of nitric oxide in pathogenesis of chronic ocular toxoplasmosis. Increased quantities of messenger RNA (mRNA) transcripts for iNOS were detected in the eyes of chronically infected C57BL/6 mice compared with noninfected control mice. Inhibition of nitric oxide (NO) by the addition of Lω‐nitro‐ l ‐arginine methyl ester ( l ‐NAME) to the drinking water of infected mice between weeks 4–6 of infection, exacerbated ocular inflammation. The amount of inflammation was assessed semiquantitatively in histological sections of the eye. Eyes from l ‐NAME treated mice showed a significant increase in inflammation of the retina ( P = 0.02), choroid ( P = 0.03), and vitreous ( P = 0.02) compared with control mice. These results demonstrate a protective role for NO in the control of chronic, ocular toxoplasmosis .