牙龈卟啉单胞菌与颈动脉斑块稳定性的相关性分析及机制探索

Correlation analysis and mechanism exploration between Porphyromonas gingivalis and carotid atherosclerotic plaque stability

目的明确牙龈卟啉单胞菌与颈动脉粥样硬化斑块稳定性的关系,并探索其中可能的机制。方法分别取15例稳定性颈动脉斑块和15例不稳定性颈动脉斑块行聚合酶链式反应(polymerase chain reaction,PCR),其中每组区分轻度、中度和重度慢性牙周炎各5例,分组行PCR扩增电泳寻找牙龈卟啉单胞菌在颈动脉斑块内的证据;对斑块内基质金属蛋白酶(matrix metalloproteinase,MMP)-2、MMP-8、MMP-9、平滑肌细胞与巨噬细胞的免疫荧光染色,分析判断斑块纤维帽内平滑肌细胞变化,探索牙龈卟啉单胞菌作用机制;随机抽取14例稳定组和14例不稳定组颈动脉斑块患者行16S rRNA高通量测序检测斑块内菌群多样性差异,验证牙龈卟啉单胞菌分布差异并探索其影响斑块稳定性的可能机制。结果不稳定组颈动脉斑块内牙龈卟啉单胞菌检出率更高(χ^(2)=5.714,P=0.017),而随着慢性牙周炎进展,牙龈卟啉单胞菌检出率明显增加(χ^(2)=6.682,P=0.035)。稳定组颈动脉斑块相对不稳定组颈动脉斑块平滑肌细胞减少,而MMP-2和MMP-8含量增高,MMP-9在两组间未见明显差异。牙龈卟啉单胞菌所在属水平在不稳定组内差异菌群较多,且丰度更高。结论牙龈卟啉单胞菌与颈动脉斑块稳定性相关,其机制可能是通过影响基质金属蛋白酶分泌,进而影响斑块稳定性。

Objective To clarify the relationship between Porphyromonas gingivalis and the stability of carotid atherosclerotic plaque,and to explore the possible mechanism.Methods A total of 15 stable carotid plaques and 15 unstable carotid plaques were selected for polymerase chain reaction(PCR)detection,and 5 cases of mild,moderate and severe chronic periodontitis were detected in each group.PCR amplification electrophoresis was performed to search for evidence of Porphyromonas gingivalis in carotid plaques.Immunofluorescence staining of matrix metalloproteinases(MMP)-2,MMP-8,MMP-9,smooth muscle cells and macrophages in the plaque were used to analyze and determine the changes of smooth muscle cells in the plaque fibrous cap,and explore the mechanism of Porphyromonas gingivalis.Fourteen patients with carotid plaque in the stable group and 14 patients with unstable group were randomly selected for 16S rRNA high-throughput sequencing to detect the diversity difference of the bacterial community in the plaque,to verify the distribution difference of Porphyromonas gingivalis, and to explore the possible mechanism of its influence on plaque stability. Results The detection rate of Porphyromonas gingivalis in carotid plaque was higher in the unstable group (χ^(2)=5.714, P=0.017), and increased significantly with the progression of chronic periodontitis (χ^(2)=6.682, P=0.035). The level of MMP-2 and MMP-8 in carotid plaques in unstable group was higher than that in stable group, the number of smooth muscle cells was less than the stable group, while MMP-9 showed no significant difference between the two groups. The level of Porphyromonas gingivalis genus in the unstable group was more diverse and the abundance was higher. Conclusion Porphyromonas gingivalis is related to the stability of carotid plaque, and the mechanism may be through affecting the secretion of matrix metalloproteinases, and then affecting the stability of plaque.