The role of nitric oxide in mice infected with Trichobilharzia regenti, the neuropathogenic schistosome

Nitric oxide (NO) has been proved to reduce parasite burden in vertebrates infected with Schistosoma, Fasciola, Brugia or Taenia. NO negatively influences parasite growth and development, which then leads to smaller parasite-caused damage to the liver during schistosomosis and stimulates healing processes in muscles infected with Toxocara canis. Peroxynitrite, formed from NO and superoxide, significantly reduces the viability of F. hepatica adults. In case of T. regenti, the neuropathogenic schistosome, the cells capable of NO production (macrophages, neutrophils, eosinophils, microglia and astrocytes) migrate to the site of the infection suggesting that NO might affect T. regenti infection as well. Therefore, the production of NO and its effect on the course of the infection was examined in vivo and the effect of peroxynitrite on T. regenti schistosomula was examined in vitro to assess the role of reactive nitrogen species during the infection. Our results from in vivo experiments demonstrate that although the infection did not significantly elevate nitrite/nitrate results in the sera, NO is locally produced in the early stages of the infection in both the skin and the spinal cord as shown by immunohistochemical detection of inducible NO synthase. Diminishing NO production by aminoguanidine..