Effects of Irrigation of Porphyromonas Gingivalis on Colonic Mechanical and Immune Barriers in Type 2 Diabetic Mice

Background Porphyromonas gingivalis (Pg.) is the main pathogen of periodontitis. Studies have found that Pg. can affect systemic diseases including type 2 diabetes mellitus (T2DM) through oral-intestinal pathway, but its specific mechanism remains unclear. Objective To explore whether Pg. has an effect on T2DM by changing intestinal mechanical and immune barriers. Methods A total of 24 among 40 SPF mice were randomly selected to construct T2DM models, among the successful models, 16 mice were selected to be divided into the model group (DM group, n=8) and model+Pg. group (PD group, n=8), and the other 16 mice were divided into the control group (N group, n=8) and Pg. group (n=8). After modeling, body mass and fasting plasma glucose (FPG) of mice were observed, and oral glucose tolerance test (OGTT) was performed at the 5th week, OGTT curve was plotted and the area under the curve (AUC) was calculated. Pg. group and PD group were gavaged with Pg. bacterial solution from the 7th week for 5 consecutive weeks. Lipopolysaccharide (LPS) was determined by enzyme-related immunosorbent assay (ELISA), colonic tight-junction protein and inflammatory factors were detected by real-time fluorescence quantitative PCR, and colonic tissue lesions were observed by hematoxylin-eosin (HE) staining. Pearson correlation or Spearman correlation analysis was used to investigate the relationship of FPG with colonic tight junction protein mRNA expression and serum LPS levels in mice. Results Body weight of DM group was higher than that of N group and Pg. group at 2nd to 6th weeks before irrigation (P