Effects of micro-amounts of Porphyromonas gingivalis lipopolysaccharide on rabbit inflammatory immune response and development of atherosclerosis.

BACKGROUND AND

OBJECTIVE

Porphyromonas gingivalis (Pg) lipopolysaccharide is associated with the immune response and atherosclerosis. This study aimed to evaluate the effects of micro-amounts of Pg-lipopolysaccharide on rabbit inflammatory immune response and the development of atherosclerosis.

MATERIAL AND

METHODS

Twenty-four New Zealand white rabbits were randomly divided into four groups (n = 6). Group A was fed a regular diet and normal saline. Group B was supplied with a high-fat diet and normal saline. Group C was treated with a normal diet and Pg-lipopolysaccharide. Group D was given a high-fat diet and Pg-lipopolysaccharide. After 14 wk, the rabbits were killed to determine the changes in pathological indices.

RESULTS

The serum lipid levels of groups B and D were significantly higher than that of group A (p < 0.01), and that of group C was higher (p < 0.05). Serum interleukin-6, monocyte chemoattractant protein-1 and tumor necrosis factor-α levels were significantly elevated by individual high-fat diets or Pg-lipopolysaccharide stimulation (p < 0.05). Groups A and C did not undergo evident aortic pathological damages, while foam cells appeared in the other two groups. Real-time polymerase chain reaction detection showed that toll-like receptor-2, interleukin-6, matrix metalloproteinase-9 and monocyte chemoattractant protein-1 were highly expressed in groups B and D (p < 0.05), and toll-like receptor-4, C-reactive protein and tumor necrosis factor-α levels were higher than those of group A (p < 0.05). Western blotting showed that transcription factor NF-κB p65 was expressed more highly in the three experimental groups than in group A (t = 9.26, p < 0.01).

CONCLUSION

Micro-amounts of Pg-lipopolysaccharide induced the high expressions of inflammatory factors and mediated the inflammatory response. Pg-lipopolysaccharide elevated the blood lipid level less significantly than the high-fat diet did, but it may promote atherosclerosis.