Anti-Toxoplasma Gondii Effect Of Tylosin In Vitro And In Vivo

Background and objectives:Toxoplasma gondii is an obligate intracellular parasite belonging to the phylum Apicomplexa.It can infect almost all warm-blooded vertebrates,including humans.According to the World Health Organization,about one-third of the world’s population is infected with T.gondii,and the infection rate among residents in China is as high as 10%.T.gondii infection usually causes no symptoms or minor damage in immunocompetent people,but it can be fatal in immunocompromised individuals.There are several genotypes of T.gondii.Although there is only a tiny(1-2%)difference in the DNA sequence among them,the proliferation,pathogenicity,and drug susceptibility of these genotypes differs noticeably.Currently,research on vaccines for human toxoplasmosis is still in the development stage and has not yet been widely applied in clinical settings.Chemical medications like pyrimethamine and sulfadiazine sodium are used to treat toxoplasmosis.However,they have severe toxic side effects.Additionally,these drugs can suppress tachyzoite growth but have no effect on tissue cysts.Therefore,it is urgent to develop highly effective and low-toxicity antiT.gondii drugs.A macrolide antibiotic called tylosin is used to treat mycoplasma infections in livestock and poultry.Tylosin has the ability to attach to bacterial ribosomes,obstruct protein synthesis,and thus impact bacterial development and growth.In this work,the anti-T.gondii activity of tylosin was evaluated both in vivo and in vitro.Research methods and results:Part Ⅰ:Virulence comparison and transcriptomic analysis of different genotypes of T.gondii1.The proliferations of RH strain and ME49 strain of T.gondii were compared in vitro,and we examined the pathogenicity of the above two strains in the mouse.It was found that there were significant differences in parasite proliferation and pathogenicity in mice.2.We discovered that different genotypes of T.gondii showed distinctive transcriptional patterns through RNA-seq technique.The RH strain displayed overexpression of 3020 genes and downregulation of 3171 genes in comparison to the ME49 strain.The differentially expressed genes were then subjected to functional annotation and pathway analysis.The dysregulated genes had an impact on genetic information processing in T.gondii and were strongly enriched in ribosome-related pathways.Part Ⅱ:Evaluation of the anti-T.gondii effect of tylosin1.In vitro study,we found tylosin significantly reduced the intracellular multiplication of T.gondii.Tylosin incubation altered several important metabolic pathways and cellular processes in T.gondii by transcriptomic analysis,with differentially expressed genes being notably enriched in the ribosome(KO03010)and ribosome synthesis pathway(KO03008).2.In vivo,tylosin,when given at a dose of 100 mg/kg by intraperitoneal injection,had a protective efficacy of 10%for RH-infected mice and 40%for ME49-infected mice,combined therapy with tylosin and sulfadiazine sodium greatly reduced the pathological damage in spleen,decreased the parasite load in animal tissues,and finally significantly raised the survival rate of infected mice.Research conclusions and significance:Tylosin significantly reduced the intracellular proliferation of different strains of T.gondii,and it alone or in combination with sulfadiazine sodium significantly improved the survival rate of infected mice.Tylosin is a novel candidate drug for toxoplasmosis,and this study also offers insights into the development of anti-T.gondii chemicals with innovative modes of action.