Combination of Lacticaseibacillus rhamnosus and Weissella confusa treatment improves ligature-induced periodontitis in rats via immune modulation and inhibition of oral pathogens

Periodontitis is a chronic inflammatory disease driven by bacterial biofilms and host immune responses. Conventional treatments, such as mechanical debridement and antibiotics, have inherent limitations. These include antibiotic resistance and incomplete pathogen elimination. Consequently, there is a growing need for novel therapeutic strategies. Probiotics represent a promising adjunct therapy due to their potential to modulate the oral microbiota and host immunity. Probiotic bacteria were isolated from infant fecal samples, and Guiyang fermented cabbage using spread plating on Man, Rogosa, and Sharpe (MRS) agar. Following isolation, candidate strains were screened in vitro for anti-inflammatory activity using an inflammatory cell model, assessing the levels of IL-1β, IL-6, and TNF-α. Subsequently, a ligature-induced rat periodontal disease model was used to evaluate the in vivo therapeutic efficacy. Clinical periodontal parameters, including probing depth and gingival bleeding, were systematically evaluated, along with assessment of inflammatory markers. In vitro screening of the anti-inflammatory capacity of six isolated probiotic strains and their combinations revealed that Lacticaseibacillus rhamnosus LHJY (LGG), Weissella confusa LHJY (W. c), and the LGG + W. c combination exhibited superior anti-inflammatory activity compared to other strains. In vitro experiments demonstrated that the probiotic combination effectively inhibited the growth of key periodontal pathogens. Furthermore, the combination exhibited potential for modulating inflammatory responses. In a ligature-induced rat periodontitis model, the combined probiotic treatment significantly improved clinical parameters, including probing depth and gingival bleeding, compared to single-strain treatments, while concurrently suppressing host inflammatory responses. These results suggest that the combined intervention of LGG and W. c, exerts a significant effect in regulating local immunity, inhibiting pathogenic bacteria, and alleviating periodontal tissue destruction. This study provides novel experimental evidence for the efficacy of a specific probiotic combination. It offers a theoretical rationale for developing targeted therapies to treat periodontitis.