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@#In order to reveal the intestinal absorption mechanism of saikosaponin d (SSd) in vitro and in vivo, the current research investigated the effects of different experimental conditions (time, concentration, temperature, pH, intestinal segments), transporter inhibitors, paracellular pathway enhancer, metabolic enzyme inhibitors on the intestinal absorption of SSd, in Caco-2 monolayers and a single pass perfusion model in rats.The results showed that the apparent permeability coefficient (Papp) and effective permeability coefficient (Peff) of SSd were 4.75 × 10-7 - 6.38 × 10-7 cm/s and 0.19 × 10-4- 0.27 × 10-4 cm/s, respectively, indicating that it was a low permeability compound, and that the transmembrane transport of SSd was concentration-dependent (0.5-5 μmol/L) and time-dependent (0-180 min).Ileum was the main absorption site for SSd. Experimental results based on Caco-2 monolayers showed that the P-gp inhibitor and paracellular permeability enhancer significantly increased the absorption of SSd (P < 0.05), which was consistent with the results obtained in rats. Inhibitors of OATPs and OCTs showed different results in vitro and in vivo, which may be related to the lower expression of them in jejunum.In summary, the intestinal absorption of SSd occurs through a carrier-mediated and energy-dependent transport, as well as passive diffusion, and P-glycoprotein plays an important role in the active transport of SSd.
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Objective To isolate and identify Prevotella nigrescens (P.nigrescens) in gingival cre-vicular fluid of patients with chronic periodontitis and to analyze its tumor-promoting role in esophageal squa-mous cell carcinoma (ESCC). Methods Samples of gingival crevicular fluid were collected from patients with chronic periodontitis and cultured on GAM agar medium under anaerobic conditions. Black colonies on GAM agar plates were picked for subculture, and then the bacteria were isolated and purified. Bacterial identification was conducted using Gram staining and 16S rDNA sequencing analysis. The isolated bacterial species was used to infect ESCC NE6-T cells and the changes in biological characteristics of the infected cells were evaluated. Results Multiple bacterial colonies were observed after anaerobic culturing of gingival cre-vicular fluid samples for 120 h on GAM agar plates. A single bacterial colony with pure black and smooth appearance was obtained from grey black bacterial colonies with streak method. It was a Gram-negative bac-terium with bead-like shape. It showed 99. 78％ 16S rDNA sequence identity with P. nigrescens F0103 and was named P. nigrescens LY01. P. nigrescens LY01 infection promoted the in vitro proliferation, migration and invasion of NE6-T cells and the growth of subcutaneous xenograft in nude mice. In addition, it could al-so induce the upregulation of Ki67 and activation of p-STAT3. Conclusions P.nigrescens inhabiting in gin-gival sulcus might promote the progression of ESCC in human with chronic periodontitis.
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Objective@#To isolate and identify Prevotella nigrescens (P.nigrescens) in gingival crevicular fluid of patients with chronic periodontitis and to analyze its tumor-promoting role in esophageal squamous cell carcinoma (ESCC).@*Methods@#Samples of gingival crevicular fluid were collected from patients with chronic periodontitis and cultured on GAM agar medium under anaerobic conditions. Black colonies on GAM agar plates were picked for subculture, and then the bacteria were isolated and purified. Bacterial identification was conducted using Gram staining and 16S rDNA sequencing analysis. The isolated bacterial species was used to infect ESCC NE6-T cells and the changes in biological characteristics of the infected cells were evaluated.@*Results@#Multiple bacterial colonies were observed after anaerobic culturing of gingival crevicular fluid samples for 120 h on GAM agar plates. A single bacterial colony with pure black and smooth appearance was obtained from grey black bacterial colonies with streak method. It was a Gram-negative bacterium with bead-like shape. It showed 99.78% 16S rDNA sequence identity with P. nigrescens F0103 and was named P. nigrescens LY01. P. nigrescens LY01 infection promoted the in vitro proliferation, migration and invasion of NE6-T cells and the growth of subcutaneous xenograft in nude mice. In addition, it could also induce the upregulation of Ki67 and activation of p-STAT3.@*Conclusions@#P. nigrescens inhabiting in gingival sulcus might promote the progression of ESCC in human with chronic periodontitis.