Construction Of Mice Model For Acute Toxoplasma Gondii Infection And Screening Drugs For Toxoplasmosis

Toxoplasma gondii is a ubiquitous, apicomplexan parasite of warm-blooded animals, and is one of the most common parasitic infections of humans. It can spread among humans and a variety of mammals. Infected animals will not only affect performance, but also it will become a source of infection human toxoplasmosis. So, prevention and treatment of the disease has important value of economics and public health. This study constructed a model of acute toxoplasmosis in mice infected with Toxoplasma gondii and then screened many drugs. We have found a significant drug (Sulfachloropyrazine). The preliminary mechanism against parasites was studied. It provides a theoretical basis for putting this drug into clinical use. The results are as follows:Toxoplasma gondii is a ubiquitous, apicomplexan parasite of warm-blooded animals, and is one of the most common parasitic infections of humans. It can spread among humans and a variety of mammals. Infected animals will not only affect performance, but also it will become a source of infection human toxoplasmosis. So, prevention and treatment of the disease has important value of economics and public health. This study constructed a model of acute toxoplasmosis in mice infected with Toxoplasma gondii and then screened many drugs. We have found a significant drug (Sulfachloropyrazine). The preliminary mechanism against parasites was studied. It provides a theoretical basis for putting this drug into clinical use. The results are as follows:1. Research the preservation method and the virulence of Toxoplasma gondii and construct a model of acute toxoplasmosis in miceWe assess the preservation methords by the pathogenicity in mice infected with toxoplasma gondii being saved and recoveried differently. Using liquid nitrogen freezing and passage method in vivo, we get the optimum way to preserve and the best time for passaging to achieve stable parasite virulence. Then, the acute Toxoplasma gondii infection model in mice has been established: Keeping Toxoplasma gondii tachyzoites in liquid nitrogen within six months and passaging twice in mice, we can get the parasites which can lead all mice infected with at least 4 000 organs die within a week. The model provides the foundation for screening new drugs and researching the biology of parasite.2. Screening drugs against Toxoplasma gondiiAs there are no great anti-toxoplasmosis drugs for animals, tens of drugs which were used as anti-protozoal or other pathogens were chosen against animal toxoplasmosis. A drug Sulfachloropyrazine were found with great efficacy, it can inhibit growth and reproduction of parasites. The survival rate of mice treated with the drug was over 50% and the survivals can live over 2 months. 3. Observe the ultrastructural changes of Toxoplasma gondii tachyzoite dealt with the drug Sulfachloropyrazine.In the normal group, considerable numbers of viable tachyzoites showed normal features under SEM and TEM. Under the SEM, in the Sulfachloropyrazine group, tachyzoites take outdifferent size, rugged and incomplete cell membrane, some parasites appear damaged and collapsed, with non-uniform reflectivity. Under the TEM, Sulfachloropyrazine group, some parasites collapse, the cell membrane and nuclear membrane structural were damaged, the number of dense granules reduce lowly. The cytoplasmic vacuoles appeared; the nucleus occured heterochromatin and other changes, pyramidal became fuzzy. After all, they appeared similar characteristics of multi-cellular apoptosis.