The Effect Of Lipopolysaccharide From Periodontal Pathogen Actinobacillus Actinomycetemcomitans On The Cytokines In Tissue-specific Monocytes/Macrophages

Objective To know the potential mechanisms of periodontal disorders on systematicdiseases and offer an idea of a potential therapy of periodontitis and some relativesystematic diseases. We compared the expression of cytokines (interlenkin-1beta,interlenkin-6, interlenkin-8, tumor necrosis factor-alpha) induced by Actinobacillusactinomycetemcomitans lipopolysaccharide (Aa-LPS) in Monocytes/Macrophagesfrom different organs of rabbits with or without hyperlipidemia. The effect ofexogenous interlenkin-10on the expression of cytokines of Monocytes/Macrophageswas also investigated.Methods New Zealand rabbits hyperlipidemia models were built by feeding withhigh-fat diet. Monocytes/macrophages were isolated from different organs of therabbits with or without hyperlipidemia, including peripheral mononuclear cells,alveolar macrophages, peritoneal macrophages and kupffer cells. And then the cellswere stimulated with Actinobacillus actinomycetemcomitans lipopolysaccharide orEscherichia coli Lipopolysaccharide or exogenous interlenkin-10. Finally, theexpression of TNF-α, IL-6, IL-1β, IL-8mRNA and proteins were determined byReal-time PCR and ELISA respectively.Results After feeding with six weeks of high-fat diet, the serum lipid parameterswere higher in the high-fat diet groups than in the regular diet groups (P<0.05), wesucceeded in modelling the hyperlipidemia models. The result of the expression ofcytokines detected by Real-time PCR and ELISA showed:(1) TheMonocytes/Macrophages from the New Zealand rabbits with normal blood lipid levelchallenged by1μg/ml E.coli-LPS or Aa-LPS had significant increases cytokines bothin mRNA and protein levels at baseline compared with the controls (P<0.05). Meanwhile the inducibility of Aa-LPS was stronger than that of E.coli-LPS (P<0.05).(2) The cells from different organs showed discrepant response when exposed toAa-LPS (P<0.05). In genaral their abilities to secrete cytokines were in the sequenceof AM>Mo>KC>PM.(3) The Monocytes/Macrophages from the rabbits withhyperlipidemia had significant increases in most of cytokines both in mRNA andprotein levels compared with the cells from the rabbits without hyperlipidemia(P<0.05).(4) Not all of the cells from different organs had the same response whenencounter with Aa-LPS under the hyperlipidemia conditions: hyperlipidemiaenhanced the expression of IL-1β, IL-6, IL-8, TNF-α in Mo and PM by Aa-LPS(P<0.05). On the contrary, the AM and KC tended to become “lower responders”when they exposed to Aa-LPS under the hyperlipidemia conditions (P<0.05).(5)Generally, the pretreated with100ng/ml IL-10could reduce the productions of TNF-α,IL-1β, IL-6, IL-8induced by Aa-LPS in monocytes/macrophages from the rabbitswith or without hyperlipidemia (P﹤0.05).Conclusion This study shows that:1. Periodontal pathogen Aa-LPS has a powerfulinducibility to stimulate proinflammatory cytokines.2. Site specific reaction ofdifferent organs monocytes/macrophages stimulated by Aa-LPS is identified.3.Hyperlipidemia accompanies with TNF-α, IL-1β, IL-6, IL-8produce.4.Hyperlipidemia can affect the expression of cytokines induced by Aa-LPS inMonocytes/Macrophages from different organs of rabbits. And the effect displaysdifferentially on them.5. IL-10can inhibit the expression of cytokines in differentorgans monocytes/macrophages.