Effect of Psoralen on the Intestinal Barrier and Alveolar Bone Loss in Rats With Chronic Periodontitis

To study the effects of psoralen on the intestinal barrier and alveolar bone loss (ABL) in rats with chronic periodontitis. Fifty-two 8-week-old specific pathogen-free (SPF) male Sprague-Dawley (SD) rats were randomly divided into the following four groups: Control group (Control), psoralen group of healthy rats (Pso), periodontitis model group (Model), and psoralen group of periodontitis rats (Peri+Pso). The alveolar bone resorption of maxillary molars was observed via haematoxylin-eosin staining and micro-computed tomography. The expression level of receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) in periodontal tissues was evaluated by immunofluorescence staining. The changes in serum tumour necrosis factor (TNF)-α, interleukin (IL)-10, IL-6, intestinal mucosal occludin, and claudin-5 were detected using enzyme-linked immunosorbent assay (ELISA). The level of intestinal mucosal NOD2 was detected using immunohistochemical methods. DNA was extracted from the intestinal contents and the 16s rRNA gene was sequenced using an Illumina MiSeq platform. The expression of NOD2 protein in the intestinal tract of periodontitis rats decreased after intragastric psoralen administration. Psoralen increased the intestinal microbiota diversity of rats. The level of serum pro-inflammatory factor TNF-α decreased and the level of anti-inflammatory factor IL-10 increased. ABL was observed to be significantly decreased in rats treated with psoralen. Psoralen decreased the RANKL/OPG ratio of periodontitis rats. Psoralen may affect the intestinal immune barrier and ecological barrier, mediate immune response, promote the secretion of anti-inflammatory factor IL-10, and reduce the secretion of the pro-inflammatory factor TNF-α, thus reducing ABL in experimental periodontitis in rats.