Stevioside reduces inflammation in periodontitis by changing the oral bacterial composition and inhibiting P. gingivalis

Background: Nowadays, excessive sugar intake is an issue for many people, and the use of sugar substitutes is becoming popular. Stevioside is considered to be a promising non-calorie sweetener with anti-inflammatory effects. However, the effects and mechanisms of it in the oral environment and periodontitis remain unclear. Therefore, we aims to explore the effect of stevioside on periodontitis in mice.Methods: The periodontitis model was established in mice treated with 0.1% stevioside, 10% glucose, or water. Micro-CT scanning was used to assess alveolar bone resorption, RT-PCR was used to evaluate the inflammatory factors expression and Porphyromonas gingivalis(P. gingivalis) invasion in the gingiva. The composition of the oral bacteria was analysed using 16S rRNA sequence in the saliva. In addition, P. gingivalis was co-cultured with stevioside in different concentrations in vitro, and bacterial activity was detected from optical density values and live/dead staining. The virulence was detected using RT-PCR, and biofilm formation was detected using scanning electron microscopy.Results: Compared with 10% glucose, the intake of 0.1% stevioside could reduce alveolar bone absorption and osteoclasts while also decreasing IL-6, TNF-a, IL-1b, and P. gingivalis in the gingiva of periodontitis mice. Moreover, the composition of the oral bacteria in the group treated with stevioside was more similar to that of the controls. In addition, in vitro stevioside reduced the bacterial activity and toxicity of P. gingivalis in a dose-dependent manner and affected its biofilm composition.Conclusion: Our research shows that compared with 10% glucose, 0.1% stevioside intake can reduce alveolar bone resorption and inflammation in periodontal tissues, and its effect on bacterial composition was making it similar to that of a healthy environment. In vitro, high concentrations of stevioside reduced P. gingivalis activity, biofilm formation, and virulence expression. Therefore, stevioside has the potential to be a beneficial alternative to glucose for patients with periodontitis.

研究背景：当前，过量糖分摄入已成为诸多人群面临的健康问题，甜味剂的应用也日益普及。甜菊糖苷（Stevioside）作为一种极具应用前景的无热量抗炎甜味剂，其在口腔环境及牙周炎中的作用与调控机制仍未明确。为此，本研究旨在探讨甜菊糖苷对小鼠牙周炎的干预效果。
实验方法：本研究构建小鼠牙周炎模型，实验小鼠分别予以0.1%甜菊糖苷、10%葡萄糖或纯水干预。采用显微计算机断层扫描（Micro-CT）评估牙槽骨吸收情况；通过实时荧光定量聚合酶链反应（RT-PCR）检测牙龈组织中炎症因子的表达水平以及牙龈卟啉单胞菌（Porphyromonas gingivalis，以下简称P. gingivalis）的侵袭情况；采集唾液样本，利用16S rRNA测序分析口腔菌群组成。此外，体外实验中将不同浓度的甜菊糖苷与P. gingivalis共培养，通过光密度值与死活染色检测细菌活性，采用RT-PCR检测细菌毒力，借助扫描电子显微镜（scanning electron microscopy）观察生物膜形成情况。
实验结果：与10%葡萄糖干预组相比，0.1%甜菊糖苷干预可减轻牙周炎小鼠的牙槽骨吸收与破骨细胞活化，同时降低牙龈组织中白细胞介素6（IL-6）、肿瘤坏死因子-α（TNF-α）、白细胞介素1β（IL-1β）的表达水平及P. gingivalis的定植量。此外，甜菊糖苷干预组的口腔菌群组成与健康对照组更为接近。体外实验证实，甜菊糖苷可通过剂量依赖性方式抑制P. gingivalis的活性与毒性，并改变其生物膜组成。
研究结论：本研究结果表明，相较于10%葡萄糖摄入，0.1%甜菊糖苷摄入可减轻牙周组织的牙槽骨吸收与炎症反应，且其对口腔菌群组成的调控作用可使菌群结构趋近于健康状态。体外实验显示，高浓度甜菊糖苷可降低P. gingivalis的活性、生物膜形成能力及毒力基因表达。综上，甜菊糖苷有望成为牙周炎患者替代葡萄糖的有益选择。