Aggregatibacter actinomycetemcomitans Lipopolysaccharide Accelerates Atherosclerosis in Spontaneously Hyperlipidemic Rabbits

Objectives: Aggregatibacter actinomycetemcomitans lipopolysaccharide (Aa-lps) is associated with immune response and atherosclerosis. We aimed to study the effects of micro-amount Aa-lps on rabbit inflammatory immune response and development of atherosclerosis.
Methods: Twenty-four New Zealand white rabbits were randomly divided into four group (n=6). The control group (ND) was fed with regular diet. The HD group was supplied with high-fat diet, the Aa-lps + ND group was treated with normal diet and Aa-lps, and the Aa-lps + HD group was given high-fat diet and Aa-lps. After 14 weeks, the rabbits were executed to determine the changes of pathological indices.
Results: The ND and Aa-lps + ND groups did not undergo evident aortic pathological damages, while foam cells appeared in the other two groups. Serum IL-6, IL-1β and TNF-α levels were significantly elevated by individual high-fat diet or Aa-lps stimulation (P < 0.05). Real-time PCR and E-lisa detection showed that TLR-2, TLR-4 and SR-A were highly expressed in the two HD groups (P < 0.05). Western blotting showed that NF-κB p65 was expressed more highly in the three experimental groups than that in the ND group (P < 0.01).
Conclusions: Micro-amount Aa-lps induced the high expressions of inflammatory factors and mediated inflammatory response. Aa-lps elevated the blood lipid level less significantly than high-fat diet did, but it may promote atherosclerosis.