Brazilian Green Propolis Suppresses The Porphyromonas Gingivalis LPS-induced M1Responses By Inhibiting NF-kB Activation In Human Macrophages

Objective and background：Chronic periodontitis is one of the most common oral chronicinflammatory diseases, it can not only lead to teeth looseness and fallingoff, but also is associated with many systemic diseases, includingcardiovascular disease, diabetes, etc. P.g is a gram-negative anaerobicbacteria, it is considered to be the main periodontal pathogens, P.g LPS,endotoxin of its cell wall composition, is the main virulence factors ofinflammatory, P.g LPS activates host immune cells macrophages throughthe surface receptors, TLR2and TLR4, after that IκB-α is phosphorylated,NF-κB is activated and goes into nuclear, which induces inflammationrelated gene transcription, produces proinflammatory factor and secretes,the periodontal connective tissue is damaged and alveolar bone isabsorption.In recent years, macrophage polarization has become a hotspot in thefield of inflammation and immunity. The activation of macrophages isdivided into classical activated macrophages (M1) and alternative activated macrophages (M2), M1has strong cytotoxicity and tissuedamage through secretion proinflammatory factors, such as iNOS，IL-1β，TNF-α, M1kills pathogens, at the same time promotes the degradation ofperiodontal connective tissue and bone tissue. M2inducesanti-inflammatory response by high expression of anti-inflammatoryfactors, such as IL-10, Arginase1, M2inhibits osteoclast proliferation,promotes tissue repair and remodeling.Brazilian propolis, experiments show that it has obvious celloxidation resistance, anti-inflammation, immunoregulation, non-toxicity,etc. Anti-inflammatory composition in Brazilian propolis has bloodcompatibility and cell membrane permeability, which can go to damagearea effectively. Our group has proved the Brazilian natural propolis caninhibit the brain macrophage, microglia, to produce inflammatory factors,so we will study whether Brazilian propolis can regulate the macrophagepolarization, and reduce the production and secretion of proinflammatoryfactors.Method：1. HE staining and immune histochemical method were used toevaluate the macrophage infiltration in the gingival tissues ofperiodontitis patients and the expression and distribution of surfacereceptors and inflammatory factors. 2. RT-PCR was used to detect P.g LPS induce macrophage cell lineTHP-1polarization3. RT-PCR and Elisa were used to measure the roles of Brazilianpropolis to P.g LPS-induced THP-1phenotype.4. Western blot method was used to evaluate the inhibitory function ofpropolis on NF-κB activation.5. Experimental results statistics were used GraphPad Prism software,single factor analysis of variance analysis.Result:1. Many infiltrated macrophages were detected in the gingival tissuesof periodontitis. Macrophage was high expression of surface receptorsTLR2and TLR4, macrophages presented M1polarization.2. P.g LPS(1μg/ml) significantly induced THP1to the M1polarization.3. Propolis(15μg/ml) significantly inhibited P.g LPS-induced THP1tothe M1polarization.4. Propolis inhibited P.g LPS-induced NF-κB activation in THP-1.Conclusion:Propolis suppresses P.g LPS-induced M1phenotype throughinhibition on NF-κB activation.