The Influence Between Microglia And Propionibacterium Pathogenic Of Fatal Bacteria Granuloma After Trauma

Fatal Bacterial Granuloma after Trauma,( FBGT) is a chronic infectious disease which is fatal and secondary to facial trauma. Now Propionibacterium acnes is identified to its pathogenic bacterium, and this bacterium which is isolated from patient has no high tox variant. P.acnes is gram-positive facultatively anacrobicrod, is belong to low tox intracellular parasitic bacteria.Since skin damage emerged, the patient of FBGT all died of brain tissue inflammation after 1.5 to 4years. Microglia is the important intracal immunocell of host which can secrete cytokine that can promote the intracranial inflammation and immune response. so study of the interaction between intracal immunocell of host and pathogenic bacteria is one of the possible paths which may play a role in the pathogenesis of FBGT. Therefore,this study maybe helpful for partly elucidating the pathogenesy of FBGT, and laying the foundation for subsequent research.In this study, the interaction between intracal immunocell of host and pathogenic bacteria is foothold pathogenic bacteria and microglia are study object. We have investigated the change of microglia in growth, phagocytosis and secretion of cytokine after the invasion of pathogenic bacteria by MTT, ELISA, PCR,in order to investigate the mode between microglia and P.acnes in immune response and elucidate the pathogenesis of FBGT.Objective:To elucidated the part pathogenesis of FBGT through interaction between microglia and P.acnes.Methods:After the interaction of pathogenic bacteria and p.acnes: take the steps as follow:1. The change of cell morphology was also observed by light microscope and electron microscope.2. The effection of Propionibacterium acnes on cell proliferation, apoptosis and phagocytosis of microglia.After microglia was affected by pathogenic bacteria of FBGT with different level and different time, we observed the influence of P.acnes on cell proliferation of microglia by detecting cytoactive with MTT method. We have observed the apoptosis situation of microglia by dectecting apoptosis and cycle with flow cytometry.3. The effection of P.acnes on the secretion of TNF-αIL-1βof microgliaThe microglia was affected by the suspension of clinical strain, standard strain and inactivate of pathogenic bacteria according to different group for 24h, then compare the difference in production of TNF-α,IL-1βof microglia in protein level and mRNA level was observed by RT-PCR, ELISA.Results:1. The microglia appeared adherent growth after passage, and it was observed by inverted microscope; after it was co-incubated with P.acnes, most microglia turned round.Microvilliis observed on cell surface by electron microscope, and the increase of lysosome was observed in microglia. The membrane invagination of microgilia to embrace bacteria was observed.2. The effection of P.acnes on cell proliferation and apoptosis of microglia:The cell energy was obviously inhibited of microglia after it was co-incubated with P.acnes for 8h and 16h.there is significant difference between experiment group and control group, P<0.05, the inhibition of P.acnes on microglia is time dependent and dose dependent. A certain apoptosis was observed in all groups, but there is significant difference between experiment group and control group,(P<0.05), there is no significant difference between each control group. Apoptosis rate upgrades with the extension of incubating time.3.The effection of P.acnes on TNF-α,IL-1βproduced by microgliaThe clinical strain and standard strain of P.acnes can promote the production of TNF-α,IL-1βof microglia, there is significant difference between experiment group and control group.(P<0.05), and there is no significant difference as compared with the inactivate bacteria group.Conclusions1. The pathogenic bacteria of Fatal Bacterial Granuloma after Trauma,( FBGT) -P.ances can inhibit the microglia growth and induce the cell apoptosis, this is may be related with inflammation induced by which the invasion of pathogenic bacteria keep on existing and not to be killed.2. P.acnes can promote microglia to produce TNF-α,IL-1β, It hints the organism can produce morning immune response by P.acne.this response probably do some damage to central nervous system。3. This study investigates the interaction feature between P.acnes and microglia in some extent, maybe helpful for lucubrating the morbility and the causing death pathogenesy of FBGT, and laying the foundation for subsequent research.