Reuterin isolated from the probiotic Lactobacillus reuteri promotes periodontal tissue regeneration by inhibiting Cx43‐mediated the intercellular transmission of endoplasmic reticulum stress

Abstract Objective The present study aimed to evaluate the effects of reuterin, a bioactive isolated from the probiotic Lactobacillus reuteri ( L. reuteri ) on periodontal tissue regeneration, and provide a new strategy for periodontitis treatment in the future. Background Data discussing the present state of the field: Probiotics are essential for maintaining oral microecological balance. Our previous study confirmed that probiotic L. reuteri extracts could rescue the function of mesenchymal stem cells (MSCs) and promote soft tissue wound healing by neutralizing inflammatory Porphyromonas gingivalis —LPS. Periodontitis is a chronic inflammatory disease caused by bacteria seriously leading to tooth loss. In this study, we isolated and purified reuterin from an extract of L. reuteri to characterize from the extracts of L. reuteri to characterize its role in promoting periodontal tissue regeneration and controlling inflammation in periodontitis. Methods Chromatographic analysis was used to isolate and purify reuterin from an extract of L. reuteri , and HNMR was used to characterize its structure. The inflammatory cytokine TNFα was used to simulate the inflammatory environment. Periodontal ligament stem cells (PDLSCs) were treated with TNFα and reuterin after which their effects were characterized using scratch wound cell migration assays to determine the concentration of reuterin, an experimental periodontitis model in rats was used to investigate the function of reuterin in periodontal regeneration and inflammation control in vivo. Real‐time PCR, dye transfer experiments, image analysis, alkaline phosphatase activity, Alizarin red staining, cell proliferation, RNA‐sequencing and Western Blot assays were used to detect the function of PDLSCs. Results In vivo, local injection of reuterin promoted periodontal tissue regeneration of experimental periodontitis in rats and reduced local inflammatory response. Moreover, we found that TNFα stimulation caused endoplasmic reticulum (ER) stress in PDLSCs, which resulted in decreased osteogenic differentiation. Treatment with reuterin inhibited the ER stress state of PDLSCs caused by the inflammatory environment and restored the osteogenic differentiation and cell proliferation functions of inflammatory PDLSCs. Mechanistically, we found that reuterin restored the functions of inflammatory PDLSCs by inhibiting the intercellular transmission of ER stress mediated by Cx43 in inflammatory PDLSCs and regulated osteogenic differentiation capacity. Conclusion Our findings identified reuterin isolated from extracts of the probiotic L. reuteri , which improves tissue regeneration and controls inflammation, thus providing a new therapeutic method for treating periodontitis.