Effects Of Probiotic Lactobacillus On Alleviation Of Chronic Periodontitis

Chronic periodontitis is the most common type of periodontitis,accounting for about 95%of patients with periodontitis.Chronic periodontitis can occur at any stage,the prevalence and severity of the disease also increase with age.Porphyromonas gingivalis is the main pathogenic bacteria of chronic periodontitis,and Fusobacterium nucleatum plays a role of "bridge" to assist the co-adhesion of P.gingivalis in the pathogenic process.In this study,P.gingivalis and F.nucleatum were the main research objects.From 204 strains of Lactobacillus,Lactobacillus with alleviating effect on chronic periodontitis and oral probiotic properties was screened out,and the effect on its existence preliminary exploration of the mechanism.The main research contents and results were as follows:(1)204 strains of Lactobacillus were screened using the mixed-bacteria biofilm model,the reduction of biofilm was used as the screening index for preliminary screening.Then the periodontitis epithelial cell model was used to regulate cell inflammatory factors and the expression of tight junction proteins.The screening results of Lactobacillus plantarum CCFM1137 and Lactobacillus fermentum CCFM1139 had an inhibitory rate of more than 40%on mixed biofilms,could regulate the expression of inflammatory factors and the tight junction proteins in cells.Lactobacillus CCFM1137 and CCFM1139 both showed high tolerance to lysozyme,had weak self-filming ability and strong self-polymerization ability.The final selected L.plantarum CCFM1137 and L.fermentum CCFM1139 not only had the effect of relieving periodontitis,but also had good oral probiotic properties.(2)The periodontitis rat model was established by combining silk ligation and periodontitis pathogenic bacteria infection,the effects of Lactobacillus CCFM1137 and CCFM1139 in the prevention and treatment of periodontitis in rats were explored.After prevention and treatment by Lactobacillus CCFM1137 and CCFM1139,the results proved that Lactobacillus CCFM1137 and CCFM1139 could significantly alleviate the weight loss caused by periodontitis in rats,reduced the formation of periodontal pockets,and relieved symptoms such as gingival swelling and bleeding.Lactobacillus CCFM1137 and CCFM1139 could reduce the colonization of periodontitis pathogenic bacteria P.gingivalis and F.nucleatum in the oral cavity by 1-2 lg CFU/m L.In addition,CCFM1137 and CCFM1139 also had a certain regulatory effect on the excessive immune response of periodontitis,and could significantly reduce the secretion of TNF-?,IL-1? and IL-8.CCFM1137 and CCFM1139 could also effectively prevent bone loss,reduce alveolar bone porosity and restore alveolar bone resorption from 5435.56 ?m to 3765.33 ?m and 3222.67 ?m,respectively.(3)Preliminary exploration of the possible mechanism of action of Lactobacillus CCFM1137 and CCFM1139 found that both strains of Lactobacillus could reduce the amount of biofilm formation and the production of extracellular polysaccharides at different stages of biofilm formation,could also reduce the number of viable bacteria of F.nucleatum and P.gingivalis in dual biofilms.Two strains of Lactobacillus could significantly down-regulate the expression of F.nucleatum outer pore membrane protein-related gene(fomA)and cell adhesionrelated gene(fadA).At the same time,two strains of Lactobacillus could regulate the expression of the virulence factor arginine gingivalin gene(RgpAcd)and fimbriae gene(FimA)of P.gingivalis.L.fermentum CCFM1139 also down-regulated the expression of the virulence factor hemagglutinin gene(HA-2)of P.gingivalis.In summary,L.plantarum CCFM1137 and L.fermentum CCFM1139 were oral probiotics with the effect of preventing and treating periodontitis,and they had broad application prospects in the development of probiotic oral care products.