Establishment Of Microglia Polarization Model And Its Effect On The Proliferation Of Toxoplasma Gondii

Toxoplasma gondii is a kind of intracellular parasitic opportunistic pathogenic protozoa.The toxoplasmosis is one of most popular parasitic diseases world widely,and could cause chronic or recessive infection.As the inherent immune components of central nervous system(CNS),microglia is one of the most vulnerable to be infection cells in the process of defense.During in CNS pathologic damage including infection,injury and other stimulation,microglia could be activation,proliferation and secretion of a large number of neurotoxic factors.Microglia are myeloid-derived cells,which are called the “brain macrophages”.Microglia have been classically classified into two main types: classical activated macrophages(CAM)and alternative activated macrophages(AAM),the M1/M2 phenotype transition process called polarization or activation.In this study,BV2 cell line as a model,the interactions between microglia and T.Gondii maybe helpful to clarify the mechanism about infection,dissemination and pathogenesis,and can provide useful reference data.Lipopolysaccharide(LPS)and interferon(IFN)-? or IL-4 were used to induce resting microglia,detecting the levels of mRNA and protein expression of M1/M2 marker molecules by PCR,western blot and Flow Cytometry.Results showed that the expression of M1-related factors was significantly up-regulated at mRNA transcription level and protein level by LPS and IFN-? stimulated microglia in vitro.Based on the polarization model in vitro,collected the cells and culture supernatant were infected with PLK strain in vitro.Detecting dynamic changes of M1/M2 markers expression by different methods.Futhermore,the phosphorylation of related signaling pathways JAK-STAT and NF-?B were further analyzed by western-blot.Compared with the control group,the infection level of M1-related marker molecules in BV2 cells was significantly up-regulated at 12 h(p<0.001),and the expression of iNOS was significantly increased after infection with T.Gondii in vitro and activated JAK-STAT1 and NF-?B signaling pathway,induced microglia to M1-type polarization.CAM has the ability to express antigen,inhibit tumor growth,and anti-pathogenic microorganisms,have the ability to inhibit or kill pathogens;AAM could secrete a variety of anti-inflammatory cytokines and chemokines and could promote tissue repair,remodeling and vascular regeneration.To evaluate the effect of M1 and M2 microglia on the proliferation of T.Gondii,The results show that proliferation of T.Gondii in M-type microglia was significantly lower than that of M0 and M2,indicating that M1-activated microglia had a significant inhibitory effect on T.Gondii proliferation.