Porphyromonas gingivalis bacteremia increases the permeability of the blood-brain barrier via the Mfsd2a/Caveolin-1 mediated transcytosis pathway / 国际口腔科学杂志·英文版

Bacteremia induced by periodontal infection is an important factor for periodontitis to threaten general health. P. gingivalis DNA/virulence factors have been found in the brain tissues from patients with Alzheimer's disease (AD). The blood-brain barrier (BBB) is essential for keeping toxic substances from entering brain tissues. However, the effect of P. gingivalis bacteremia on BBB permeability and its underlying mechanism remains unclear. In the present study, rats were injected by tail vein with P. gingivalis three times a week for eight weeks to induce bacteremia. An in vitro BBB model infected with P. gingivalis was also established. We found that the infiltration of Evans blue dye and Albumin protein deposition in the rat brain tissues were increased in the rat brain tissues with P. gingivalis bacteremia and P. gingivalis could pass through the in vitro BBB model. Caveolae were detected after P. gingivalis infection in BMECs both in vivo and in vitro. Caveolin-1 (Cav-1) expression was enhanced after P. gingivalis infection. Downregulation of Cav-1 rescued P. gingivalis-enhanced BMECs permeability. We further found P. gingivalis-gingipain could be colocalized with Cav-1 and the strong hydrogen bonding between Cav-1 and arg-specific-gingipain (RgpA) were detected. Moreover, P. gingivalis significantly inhibited the major facilitator superfamily domain containing 2a (Mfsd2a) expression. Mfsd2a overexpression reversed P. gingivalis-increased BMECs permeability and Cav-1 expression. These results revealed that Mfsd2a/Cav-1 mediated transcytosis is a key pathway governing BBB BMECs permeability induced by P. gingivalis, which may contribute to P. gingivalis/virulence factors entrance and the subsequent neurological impairments.

The inhibitory effects of chlorhexidine in the development of rat periodontitis models / 实用口腔医学杂志

Objective:To investigate the inhibitory effects of different concentrations of chlorhexidine in the development of peri-odontitis models in rats.Methods:periodontitis models were established by the ligation of bilateral first molars and orally challenge with P.gingivalis W83.0.05%,0.1%,0.2% and 0.5% chlorhexidine were used to wash the periodontal pocket and oral mucosa of the rats.4 weeks later,absolute real time quantitative PCR was used to count the copy of P.gingivalis W83 in rat periodontal pockets.Scanning electron microscopy was used to observe the distribution of P.gingivalis W83 on rat teeth surface.Immunohisto-chemical technique was used to detect the expression of TNF-αin gingival tissue of the rats.Results:0.2% and 0.5% chlorhexi-dine reduced the copy of P.gingivalis W83 on teeth surface and in periodontal pockets (P <0.05);0.1% -0.5% chlorhexidine reduced the expression of TNF-αin gingival tissue (P <0.05).Conclusion:0.1% -0.2% chlorhexidine can inhibit the develop-ment of chronic periodontitis in rats.

Study on Processing of Fructus Crataegi / 中成药

In this experiment, the crude Fructus Crataegi, its baked product, the products baked to dark brown and baked to charcoal were compared regarding the gastrointestinal promote function of rat, the content of free acids in stomach, total acids, pepsin and nitrite as indices. As a result, the crude and the fried product possessed greater effects on the digestive ability of rats, but their nitrite content was lower. It was preliminary suggested that adding the crude and the fried product into digestant be an optimum selection