Activation of TLRs/NF-κB signal pathway and occurrence of different functional cytokines during invasive pulmonary aspergillosis / 中华微生物学和免疫学杂志

ABSTRACT

Objective To study the activation of TLRs/NF-κB signal pathway and production of different functional cytokines during invasive pulmonary aspergillosis( IPA) , in order to probe the pathogene-sis of IPA. Methods Mouse were randomly divided into normal, normal + inoculated with Aspergillus fumigatus( normal inoculation group), and immune suppression + inoculation with Aspergillus fumigatus (IPAmodel group) , the mouse were killed at different time points after inhaling Aspergillus fumigatus spores by nose. Removing the lung tissue in a sterile manner and making pathological section respectively, counting Aspergillus fumigatus colony, dynamiclly detecting the expression of TLR2, TLR4 mRNA, variation of NF-κB p65 protein, pro-inflammatory cytokines TNF-α, IL-1β and anti-inflammatory cytokines IL-10 levels in the lung tissue by RT-PCR and Western blot method during Aspergillus fumigatus infection in mouse. Results (1) When it's 72 h after inhaling Aspergillus fumigatus by nose, IPA model emerged severe lung tissue inflammation, and generated a large number of hyphae, meanwhile, burthen of Aspergillus fumigatus was higher than normal inoculation group at each time point. (2)Compared with the normal inoculation group, IPA group whose TLR2 mRNA was low expression at early stage of infection (24 h), and emerged high expression at late stage of infection (120 h, 144 h); and TLR4 mRNA has been at a state of low expression in the infection process; NF-κB p65 suddenly increased at early stage of infection(24 h) and then continued to decline. (3) After infected by Aspergillus fumigatus in normal mouse, proinflammatory cytokine TNF-α, IL-1β in lung exhibited high expression at the early stages of infection, and the highest expression levels appeared at 48 h or 72 h, then decreased and recovered to normal level. And the expression level of anti-inflammatory cytokine IL-10 rised at late stage of infection; The IP A mouse released a lot of anti-inflammatory cytokine IL-10 at early stage of infection, which significantly reduced at late stage, and released pro-inflammatory cyto-kines TNF-α, IL-1β at slow and low level. Conclusion The abnormal activation of TLRs/NF-β signaling pathway caused the loss of dynamic balance between pro-inflammatory cytokines and anti-inflammatory cytokines, leading to the occurrence and development of IPA.