Hu Mei Qing Yan Ke Li Alleviates Periodontitis by Modulating the Oral Microbiome

Periodontitis is a prevalent chronic inflammatory disease driven by dysbiosis of the oral microbiota. Hu Mei Qing Yan Ke Li (HM), a modern herbal formulation derived from Reynoutria japonica Houtt and Prunus mume Siebold & Zucc, exhibits anti-inflammatory, antioxidant, and antibacterial properties, suggesting promising therapeutic potential for periodontitis therapy. This study aimed to investigate the protective effects of HM against experimental periodontitis and further explore its underlying mechanisms.

Periodontitis was induced by ligature placement in C57BL/6 mice. Mice were randomly assigned to the untreated periodontitis (P) and HM-treated (P + HM) groups. Mice in the P + HM group received HM via daily oral gavage at 6.58 mg/g body weight for 2 weeks. Alveolar bone loss was assessed by micro-CT analysis. Periodontal tissue destruction and osteoclast activity were evaluated by H&E, Masson's, and TRAP staining. Expression of OPG and RANKL was detected by immunofluorescence. Subgingival microbiota composition was analyzed by 16S rRNA sequencing.

HM treatment significantly inhibited osteoclastogenesis and alleviated alveolar bone resorption, while preserving periodontal tissue integrity. Quantitatively, HM treatment significantly increased BV/TV from 41.89% to 54.41% (p = 0.0019), Tb.Th from 111.5 to 131.2 µm (p = 0.0028), and Tb.Sp from 119.2 to 153.6 µm (p = 0.0015), while decreasing BS/BV from 0.03166 to 0.02655 1/µm (p = 0.0004). Mechanistically, HM upregulated OPG and downregulated RANKL expression in periodontal tissues. Notably, HM restructured the subgingival microbial community, suppressing the pathobiont Streptococcus acidominimus (16.95%-9.37%, p = 0.0411) and Rodentibacter_A_734545pneumotropicus (70.32%-16.46%, p < 0.0001), while enriching a beneficial consortium including Streptococcus danieliae (0.75%-30.68%, p < 0.0001), unclassified Corynebacterium (0.00%-6.50%, p = 0.0022), and unclassified Ligilactobacillus (1.57%-22.74%, p = 0.0063).

HM alleviates periodontitis by remodeling the dysbiotic oral microbiome toward homeostasis and favorably modulating the OPG/RANKL axis in a murine ligature-induced periodontitis model.